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/linux-master/Documentation/ | ||
H A D | dontdiff | diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
/linux-master/include/linux/ | ||
H A D | moduleparam.h | diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
H A D | module.h | diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 942e4431 Tue Sep 03 01:03:57 MDT 2013 Li Zhong <zhong@linux.vnet.ibm.com> module: Fix mod->mkobj.kobj potentially freed too early DEBUG_KOBJECT_RELEASE helps to find the issue attached below. After some investigation, it seems the reason is: The mod->mkobj.kobj(ffffffffa01600d0 below) is freed together with mod itself in free_module(). However, its children still hold references to it, as the delay caused by DEBUG_KOBJECT_RELEASE. So when the child(holders below) tries to decrease the reference count to its parent in kobject_del(), BUG happens as it tries to access already freed memory. This patch tries to fix it by waiting for the mod->mkobj.kobj to be really released in the module removing process (and some error code paths). [ 1844.175287] kobject: 'holders' (ffff88007c1f1600): kobject_release, parent ffffffffa01600d0 (delayed) [ 1844.178991] kobject: 'notes' (ffff8800370b2a00): kobject_release, parent ffffffffa01600d0 (delayed) [ 1845.180118] kobject: 'holders' (ffff88007c1f1600): kobject_cleanup, parent ffffffffa01600d0 [ 1845.182130] kobject: 'holders' (ffff88007c1f1600): auto cleanup kobject_del [ 1845.184120] BUG: unable to handle kernel paging request at ffffffffa01601d0 [ 1845.185026] IP: [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] PGD 1a13067 PUD 1a14063 PMD 7bd30067 PTE 0 [ 1845.185026] Oops: 0000 [#1] PREEMPT [ 1845.185026] Modules linked in: xfs libcrc32c [last unloaded: kprobe_example] [ 1845.185026] CPU: 0 PID: 18 Comm: kworker/0:1 Tainted: G O 3.11.0-rc6-next-20130819+ #1 [ 1845.185026] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 1845.185026] Workqueue: events kobject_delayed_cleanup [ 1845.185026] task: ffff88007ca51f00 ti: ffff88007ca5c000 task.ti: ffff88007ca5c000 [ 1845.185026] RIP: 0010:[<ffffffff812cda81>] [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP: 0018:ffff88007ca5dd08 EFLAGS: 00010282 [ 1845.185026] RAX: 0000000000002000 RBX: ffffffffa01600d0 RCX: ffffffff8177d638 [ 1845.185026] RDX: ffff88007ca5dc18 RSI: 0000000000000000 RDI: ffffffffa01600d0 [ 1845.185026] RBP: ffff88007ca5dd18 R08: ffffffff824e9810 R09: ffffffffffffffff [ 1845.185026] R10: ffff8800ffffffff R11: dead4ead00000001 R12: ffffffff81a95040 [ 1845.185026] R13: ffff88007b27a960 R14: ffff88007c1f1600 R15: 0000000000000000 [ 1845.185026] FS: 0000000000000000(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000 [ 1845.185026] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1845.185026] CR2: ffffffffa01601d0 CR3: 0000000037207000 CR4: 00000000000006b0 [ 1845.185026] Stack: [ 1845.185026] ffff88007c1f1600 ffff88007c1f1600 ffff88007ca5dd38 ffffffff812cdb7e [ 1845.185026] 0000000000000000 ffff88007c1f1640 ffff88007ca5dd68 ffffffff812cdbfe [ 1845.185026] ffff88007c974800 ffff88007c1f1640 ffff88007ff61a00 0000000000000000 [ 1845.185026] Call Trace: [ 1845.185026] [<ffffffff812cdb7e>] kobject_del+0x2e/0x40 [ 1845.185026] [<ffffffff812cdbfe>] kobject_delayed_cleanup+0x6e/0x1d0 [ 1845.185026] [<ffffffff81063a45>] process_one_work+0x1e5/0x670 [ 1845.185026] [<ffffffff810639e3>] ? process_one_work+0x183/0x670 [ 1845.185026] [<ffffffff810642b3>] worker_thread+0x113/0x370 [ 1845.185026] [<ffffffff810641a0>] ? rescuer_thread+0x290/0x290 [ 1845.185026] [<ffffffff8106bfba>] kthread+0xda/0xe0 [ 1845.185026] [<ffffffff814ff0f0>] ? _raw_spin_unlock_irq+0x30/0x60 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] [<ffffffff8150751a>] ret_from_fork+0x7a/0xb0 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] Code: 81 48 c7 c7 28 95 ad 81 31 c0 e8 9b da 01 00 e9 4f ff ff ff 66 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 85 ff 74 1d <f6> 87 00 01 00 00 01 74 1e 48 8d 7b 38 83 6b 38 01 0f 94 c0 84 [ 1845.185026] RIP [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP <ffff88007ca5dd08> [ 1845.185026] CR2: ffffffffa01601d0 [ 1845.185026] ---[ end trace 49a70afd109f5653 ]--- Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> diff 942e4431 Tue Sep 03 01:03:57 MDT 2013 Li Zhong <zhong@linux.vnet.ibm.com> module: Fix mod->mkobj.kobj potentially freed too early DEBUG_KOBJECT_RELEASE helps to find the issue attached below. After some investigation, it seems the reason is: The mod->mkobj.kobj(ffffffffa01600d0 below) is freed together with mod itself in free_module(). However, its children still hold references to it, as the delay caused by DEBUG_KOBJECT_RELEASE. So when the child(holders below) tries to decrease the reference count to its parent in kobject_del(), BUG happens as it tries to access already freed memory. This patch tries to fix it by waiting for the mod->mkobj.kobj to be really released in the module removing process (and some error code paths). [ 1844.175287] kobject: 'holders' (ffff88007c1f1600): kobject_release, parent ffffffffa01600d0 (delayed) [ 1844.178991] kobject: 'notes' (ffff8800370b2a00): kobject_release, parent ffffffffa01600d0 (delayed) [ 1845.180118] kobject: 'holders' (ffff88007c1f1600): kobject_cleanup, parent ffffffffa01600d0 [ 1845.182130] kobject: 'holders' (ffff88007c1f1600): auto cleanup kobject_del [ 1845.184120] BUG: unable to handle kernel paging request at ffffffffa01601d0 [ 1845.185026] IP: [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] PGD 1a13067 PUD 1a14063 PMD 7bd30067 PTE 0 [ 1845.185026] Oops: 0000 [#1] PREEMPT [ 1845.185026] Modules linked in: xfs libcrc32c [last unloaded: kprobe_example] [ 1845.185026] CPU: 0 PID: 18 Comm: kworker/0:1 Tainted: G O 3.11.0-rc6-next-20130819+ #1 [ 1845.185026] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 1845.185026] Workqueue: events kobject_delayed_cleanup [ 1845.185026] task: ffff88007ca51f00 ti: ffff88007ca5c000 task.ti: ffff88007ca5c000 [ 1845.185026] RIP: 0010:[<ffffffff812cda81>] [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP: 0018:ffff88007ca5dd08 EFLAGS: 00010282 [ 1845.185026] RAX: 0000000000002000 RBX: ffffffffa01600d0 RCX: ffffffff8177d638 [ 1845.185026] RDX: ffff88007ca5dc18 RSI: 0000000000000000 RDI: ffffffffa01600d0 [ 1845.185026] RBP: ffff88007ca5dd18 R08: ffffffff824e9810 R09: ffffffffffffffff [ 1845.185026] R10: ffff8800ffffffff R11: dead4ead00000001 R12: ffffffff81a95040 [ 1845.185026] R13: ffff88007b27a960 R14: ffff88007c1f1600 R15: 0000000000000000 [ 1845.185026] FS: 0000000000000000(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000 [ 1845.185026] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1845.185026] CR2: ffffffffa01601d0 CR3: 0000000037207000 CR4: 00000000000006b0 [ 1845.185026] Stack: [ 1845.185026] ffff88007c1f1600 ffff88007c1f1600 ffff88007ca5dd38 ffffffff812cdb7e [ 1845.185026] 0000000000000000 ffff88007c1f1640 ffff88007ca5dd68 ffffffff812cdbfe [ 1845.185026] ffff88007c974800 ffff88007c1f1640 ffff88007ff61a00 0000000000000000 [ 1845.185026] Call Trace: [ 1845.185026] [<ffffffff812cdb7e>] kobject_del+0x2e/0x40 [ 1845.185026] [<ffffffff812cdbfe>] kobject_delayed_cleanup+0x6e/0x1d0 [ 1845.185026] [<ffffffff81063a45>] process_one_work+0x1e5/0x670 [ 1845.185026] [<ffffffff810639e3>] ? process_one_work+0x183/0x670 [ 1845.185026] [<ffffffff810642b3>] worker_thread+0x113/0x370 [ 1845.185026] [<ffffffff810641a0>] ? rescuer_thread+0x290/0x290 [ 1845.185026] [<ffffffff8106bfba>] kthread+0xda/0xe0 [ 1845.185026] [<ffffffff814ff0f0>] ? _raw_spin_unlock_irq+0x30/0x60 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] [<ffffffff8150751a>] ret_from_fork+0x7a/0xb0 [ 1845.185026] [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] Code: 81 48 c7 c7 28 95 ad 81 31 c0 e8 9b da 01 00 e9 4f ff ff ff 66 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 85 ff 74 1d <f6> 87 00 01 00 00 01 74 1e 48 8d 7b 38 83 6b 38 01 0f 94 c0 84 [ 1845.185026] RIP [<ffffffff812cda81>] kobject_put+0x11/0x60 [ 1845.185026] RSP <ffff88007ca5dd08> [ 1845.185026] CR2: ffffffffa01601d0 [ 1845.185026] ---[ end trace 49a70afd109f5653 ]--- Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> |
/linux-master/ | ||
H A D | .gitignore | diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
H A D | Makefile | diff 39218ff4 Thu Apr 01 17:23:44 MDT 2021 Kees Cook <keescook@chromium.org> stack: Optionally randomize kernel stack offset each syscall This provides the ability for architectures to enable kernel stack base address offset randomization. This feature is controlled by the boot param "randomize_kstack_offset=on/off", with its default value set by CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT. This feature is based on the original idea from the last public release of PaX's RANDKSTACK feature: https://pax.grsecurity.net/docs/randkstack.txt All the credit for the original idea goes to the PaX team. Note that the design and implementation of this upstream randomize_kstack_offset feature differs greatly from the RANDKSTACK feature (see below). Reasoning for the feature: This feature aims to make harder the various stack-based attacks that rely on deterministic stack structure. We have had many such attacks in past (just to name few): https://jon.oberheide.org/files/infiltrate12-thestackisback.pdf https://jon.oberheide.org/files/stackjacking-infiltrate11.pdf https://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html As Linux kernel stack protections have been constantly improving (vmap-based stack allocation with guard pages, removal of thread_info, STACKLEAK), attackers have had to find new ways for their exploits to work. They have done so, continuing to rely on the kernel's stack determinism, in situations where VMAP_STACK and THREAD_INFO_IN_TASK_STRUCT were not relevant. For example, the following recent attacks would have been hampered if the stack offset was non-deterministic between syscalls: https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf (page 70: targeting the pt_regs copy with linear stack overflow) https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html (leaked stack address from one syscall as a target during next syscall) The main idea is that since the stack offset is randomized on each system call, it is harder for an attack to reliably land in any particular place on the thread stack, even with address exposures, as the stack base will change on the next syscall. Also, since randomization is performed after placing pt_regs, the ptrace-based approach[1] to discover the randomized offset during a long-running syscall should not be possible. Design description: During most of the kernel's execution, it runs on the "thread stack", which is pretty deterministic in its structure: it is fixed in size, and on every entry from userspace to kernel on a syscall the thread stack starts construction from an address fetched from the per-cpu cpu_current_top_of_stack variable. The first element to be pushed to the thread stack is the pt_regs struct that stores all required CPU registers and syscall parameters. Finally the specific syscall function is called, with the stack being used as the kernel executes the resulting request. The goal of randomize_kstack_offset feature is to add a random offset after the pt_regs has been pushed to the stack and before the rest of the thread stack is used during the syscall processing, and to change it every time a process issues a syscall. The source of randomness is currently architecture-defined (but x86 is using the low byte of rdtsc()). Future improvements for different entropy sources is possible, but out of scope for this patch. Further more, to add more unpredictability, new offsets are chosen at the end of syscalls (the timing of which should be less easy to measure from userspace than at syscall entry time), and stored in a per-CPU variable, so that the life of the value does not stay explicitly tied to a single task. As suggested by Andy Lutomirski, the offset is added using alloca() and an empty asm() statement with an output constraint, since it avoids changes to assembly syscall entry code, to the unwinder, and provides correct stack alignment as defined by the compiler. In order to make this available by default with zero performance impact for those that don't want it, it is boot-time selectable with static branches. This way, if the overhead is not wanted, it can just be left turned off with no performance impact. The generated assembly for x86_64 with GCC looks like this: ... ffffffff81003977: 65 8b 05 02 ea 00 7f mov %gs:0x7f00ea02(%rip),%eax # 12380 <kstack_offset> ffffffff8100397e: 25 ff 03 00 00 and $0x3ff,%eax ffffffff81003983: 48 83 c0 0f add $0xf,%rax ffffffff81003987: 25 f8 07 00 00 and $0x7f8,%eax ffffffff8100398c: 48 29 c4 sub %rax,%rsp ffffffff8100398f: 48 8d 44 24 0f lea 0xf(%rsp),%rax ffffffff81003994: 48 83 e0 f0 and $0xfffffffffffffff0,%rax ... As a result of the above stack alignment, this patch introduces about 5 bits of randomness after pt_regs is spilled to the thread stack on x86_64, and 6 bits on x86_32 (since its has 1 fewer bit required for stack alignment). The amount of entropy could be adjusted based on how much of the stack space we wish to trade for security. My measure of syscall performance overhead (on x86_64): lmbench: /usr/lib/lmbench/bin/x86_64-linux-gnu/lat_syscall -N 10000 null randomize_kstack_offset=y Simple syscall: 0.7082 microseconds randomize_kstack_offset=n Simple syscall: 0.7016 microseconds So, roughly 0.9% overhead growth for a no-op syscall, which is very manageable. And for people that don't want this, it's off by default. There are two gotchas with using the alloca() trick. First, compilers that have Stack Clash protection (-fstack-clash-protection) enabled by default (e.g. Ubuntu[3]) add pagesize stack probes to any dynamic stack allocations. While the randomization offset is always less than a page, the resulting assembly would still contain (unreachable!) probing routines, bloating the resulting assembly. To avoid this, -fno-stack-clash-protection is unconditionally added to the kernel Makefile since this is the only dynamic stack allocation in the kernel (now that VLAs have been removed) and it is provably safe from Stack Clash style attacks. The second gotcha with alloca() is a negative interaction with -fstack-protector*, in that it sees the alloca() as an array allocation, which triggers the unconditional addition of the stack canary function pre/post-amble which slows down syscalls regardless of the static branch. In order to avoid adding this unneeded check and its associated performance impact, architectures need to carefully remove uses of -fstack-protector-strong (or -fstack-protector) in the compilation units that use the add_random_kstack() macro and to audit the resulting stack mitigation coverage (to make sure no desired coverage disappears). No change is visible for this on x86 because the stack protector is already unconditionally disabled for the compilation unit, but the change is required on arm64. There is, unfortunately, no attribute that can be used to disable stack protector for specific functions. Comparison to PaX RANDKSTACK feature: The RANDKSTACK feature randomizes the location of the stack start (cpu_current_top_of_stack), i.e. including the location of pt_regs structure itself on the stack. Initially this patch followed the same approach, but during the recent discussions[2], it has been determined to be of a little value since, if ptrace functionality is available for an attacker, they can use PTRACE_PEEKUSR/PTRACE_POKEUSR to read/write different offsets in the pt_regs struct, observe the cache behavior of the pt_regs accesses, and figure out the random stack offset. Another difference is that the random offset is stored in a per-cpu variable, rather than having it be per-thread. As a result, these implementations differ a fair bit in their implementation details and results, though obviously the intent is similar. [1] https://lore.kernel.org/kernel-hardening/2236FBA76BA1254E88B949DDB74E612BA4BC57C1@IRSMSX102.ger.corp.intel.com/ [2] https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/ [3] https://lists.ubuntu.com/archives/ubuntu-devel/2019-June/040741.html Co-developed-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210401232347.2791257-4-keescook@chromium.org diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 39218ff4 Thu Apr 01 17:23:44 MDT 2021 Kees Cook <keescook@chromium.org> stack: Optionally randomize kernel stack offset each syscall This provides the ability for architectures to enable kernel stack base address offset randomization. This feature is controlled by the boot param "randomize_kstack_offset=on/off", with its default value set by CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT. This feature is based on the original idea from the last public release of PaX's RANDKSTACK feature: https://pax.grsecurity.net/docs/randkstack.txt All the credit for the original idea goes to the PaX team. Note that the design and implementation of this upstream randomize_kstack_offset feature differs greatly from the RANDKSTACK feature (see below). Reasoning for the feature: This feature aims to make harder the various stack-based attacks that rely on deterministic stack structure. We have had many such attacks in past (just to name few): https://jon.oberheide.org/files/infiltrate12-thestackisback.pdf https://jon.oberheide.org/files/stackjacking-infiltrate11.pdf https://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html As Linux kernel stack protections have been constantly improving (vmap-based stack allocation with guard pages, removal of thread_info, STACKLEAK), attackers have had to find new ways for their exploits to work. They have done so, continuing to rely on the kernel's stack determinism, in situations where VMAP_STACK and THREAD_INFO_IN_TASK_STRUCT were not relevant. For example, the following recent attacks would have been hampered if the stack offset was non-deterministic between syscalls: https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf (page 70: targeting the pt_regs copy with linear stack overflow) https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html (leaked stack address from one syscall as a target during next syscall) The main idea is that since the stack offset is randomized on each system call, it is harder for an attack to reliably land in any particular place on the thread stack, even with address exposures, as the stack base will change on the next syscall. Also, since randomization is performed after placing pt_regs, the ptrace-based approach[1] to discover the randomized offset during a long-running syscall should not be possible. Design description: During most of the kernel's execution, it runs on the "thread stack", which is pretty deterministic in its structure: it is fixed in size, and on every entry from userspace to kernel on a syscall the thread stack starts construction from an address fetched from the per-cpu cpu_current_top_of_stack variable. The first element to be pushed to the thread stack is the pt_regs struct that stores all required CPU registers and syscall parameters. Finally the specific syscall function is called, with the stack being used as the kernel executes the resulting request. The goal of randomize_kstack_offset feature is to add a random offset after the pt_regs has been pushed to the stack and before the rest of the thread stack is used during the syscall processing, and to change it every time a process issues a syscall. The source of randomness is currently architecture-defined (but x86 is using the low byte of rdtsc()). Future improvements for different entropy sources is possible, but out of scope for this patch. Further more, to add more unpredictability, new offsets are chosen at the end of syscalls (the timing of which should be less easy to measure from userspace than at syscall entry time), and stored in a per-CPU variable, so that the life of the value does not stay explicitly tied to a single task. As suggested by Andy Lutomirski, the offset is added using alloca() and an empty asm() statement with an output constraint, since it avoids changes to assembly syscall entry code, to the unwinder, and provides correct stack alignment as defined by the compiler. In order to make this available by default with zero performance impact for those that don't want it, it is boot-time selectable with static branches. This way, if the overhead is not wanted, it can just be left turned off with no performance impact. The generated assembly for x86_64 with GCC looks like this: ... ffffffff81003977: 65 8b 05 02 ea 00 7f mov %gs:0x7f00ea02(%rip),%eax # 12380 <kstack_offset> ffffffff8100397e: 25 ff 03 00 00 and $0x3ff,%eax ffffffff81003983: 48 83 c0 0f add $0xf,%rax ffffffff81003987: 25 f8 07 00 00 and $0x7f8,%eax ffffffff8100398c: 48 29 c4 sub %rax,%rsp ffffffff8100398f: 48 8d 44 24 0f lea 0xf(%rsp),%rax ffffffff81003994: 48 83 e0 f0 and $0xfffffffffffffff0,%rax ... As a result of the above stack alignment, this patch introduces about 5 bits of randomness after pt_regs is spilled to the thread stack on x86_64, and 6 bits on x86_32 (since its has 1 fewer bit required for stack alignment). The amount of entropy could be adjusted based on how much of the stack space we wish to trade for security. My measure of syscall performance overhead (on x86_64): lmbench: /usr/lib/lmbench/bin/x86_64-linux-gnu/lat_syscall -N 10000 null randomize_kstack_offset=y Simple syscall: 0.7082 microseconds randomize_kstack_offset=n Simple syscall: 0.7016 microseconds So, roughly 0.9% overhead growth for a no-op syscall, which is very manageable. And for people that don't want this, it's off by default. There are two gotchas with using the alloca() trick. First, compilers that have Stack Clash protection (-fstack-clash-protection) enabled by default (e.g. Ubuntu[3]) add pagesize stack probes to any dynamic stack allocations. While the randomization offset is always less than a page, the resulting assembly would still contain (unreachable!) probing routines, bloating the resulting assembly. To avoid this, -fno-stack-clash-protection is unconditionally added to the kernel Makefile since this is the only dynamic stack allocation in the kernel (now that VLAs have been removed) and it is provably safe from Stack Clash style attacks. The second gotcha with alloca() is a negative interaction with -fstack-protector*, in that it sees the alloca() as an array allocation, which triggers the unconditional addition of the stack canary function pre/post-amble which slows down syscalls regardless of the static branch. In order to avoid adding this unneeded check and its associated performance impact, architectures need to carefully remove uses of -fstack-protector-strong (or -fstack-protector) in the compilation units that use the add_random_kstack() macro and to audit the resulting stack mitigation coverage (to make sure no desired coverage disappears). No change is visible for this on x86 because the stack protector is already unconditionally disabled for the compilation unit, but the change is required on arm64. There is, unfortunately, no attribute that can be used to disable stack protector for specific functions. Comparison to PaX RANDKSTACK feature: The RANDKSTACK feature randomizes the location of the stack start (cpu_current_top_of_stack), i.e. including the location of pt_regs structure itself on the stack. Initially this patch followed the same approach, but during the recent discussions[2], it has been determined to be of a little value since, if ptrace functionality is available for an attacker, they can use PTRACE_PEEKUSR/PTRACE_POKEUSR to read/write different offsets in the pt_regs struct, observe the cache behavior of the pt_regs accesses, and figure out the random stack offset. Another difference is that the random offset is stored in a per-cpu variable, rather than having it be per-thread. As a result, these implementations differ a fair bit in their implementation details and results, though obviously the intent is similar. [1] https://lore.kernel.org/kernel-hardening/2236FBA76BA1254E88B949DDB74E612BA4BC57C1@IRSMSX102.ger.corp.intel.com/ [2] https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/ [3] https://lists.ubuntu.com/archives/ubuntu-devel/2019-June/040741.html Co-developed-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210401232347.2791257-4-keescook@chromium.org diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
/linux-master/scripts/ | ||
H A D | link-vmlinux.sh | diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> |
/linux-master/include/asm-generic/ | ||
H A D | vmlinux.lds.h | diff 6ca63662 Wed Jun 05 14:32:22 MDT 2019 Sven Schnelle <svens@stackframe.org> parisc: add dynamic ftrace This patch implements dynamic ftrace for PA-RISC. The required mcount call sequences can get pretty long, so instead of patching the whole call sequence out of the functions, we are using -fpatchable-function-entry from gcc. This puts a configurable amount of NOPS before/at the start of the function. Taking do_sys_open() as example, which would look like this when the call is patched out: 1036b248: 08 00 02 40 nop 1036b24c: 08 00 02 40 nop 1036b250: 08 00 02 40 nop 1036b254: 08 00 02 40 nop 1036b258 <do_sys_open>: 1036b258: 08 00 02 40 nop 1036b25c: 08 03 02 41 copy r3,r1 1036b260: 6b c2 3f d9 stw rp,-14(sp) 1036b264: 08 1e 02 43 copy sp,r3 1036b268: 6f c1 01 00 stw,ma r1,80(sp) When ftrace gets enabled for this function the kernel will patch these NOPs to: 1036b248: 10 19 57 20 <address of ftrace> 1036b24c: 6f c1 00 80 stw,ma r1,40(sp) 1036b250: 48 21 3f d1 ldw -18(r1),r1 1036b254: e8 20 c0 02 bv,n r0(r1) 1036b258 <do_sys_open>: 1036b258: e8 3f 1f df b,l,n .-c,r1 1036b25c: 08 03 02 41 copy r3,r1 1036b260: 6b c2 3f d9 stw rp,-14(sp) 1036b264: 08 1e 02 43 copy sp,r3 1036b268: 6f c1 01 00 stw,ma r1,80(sp) So the first NOP in do_sys_open() will be patched to jump backwards into some minimal trampoline code which pushes a stackframe, saves r1 which holds the return address, loads the address of the real ftrace function, and branches to that location. For 64 Bit things are getting a bit more complicated (and longer) because we must make sure that the address of ftrace location is 8 byte aligned, and the offset passed to ldd for fetching the address is 8 byte aligned as well. Note that gcc has a bug which misplaces the function label, and needs a patch to make dynamic ftrace work. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90751 for details. Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff 898490c0 Mon Apr 29 10:11:14 MDT 2019 Alexey Gladkov <gladkov.alexey@gmail.com> moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org> Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> diff ffe8018c Fri Sep 17 16:24:11 MDT 2010 Hendrik Brueckner <brueckner@linux.vnet.ibm.com> initramfs: fix initramfs size calculation The size of a built-in initramfs is calculated in init/initramfs.c by "__initramfs_end - __initramfs_start". Those symbols are defined in the linker script include/asm-generic/vmlinux.lds.h: #define INIT_RAM_FS \ . = ALIGN(PAGE_SIZE); \ VMLINUX_SYMBOL(__initramfs_start) = .; \ *(.init.ramfs) \ VMLINUX_SYMBOL(__initramfs_end) = .; If the initramfs file has an odd number of bytes, the "__initramfs_end" symbol points to an odd address, for example, the symbols in the System.map might look like: 0000000000572000 T __initramfs_start 00000000005bcd05 T __initramfs_end <-- odd address At least on s390 this causes a problem: Certain s390 instructions, especially instructions for loading addresses (larl) or branch addresses must be on even addresses. The compiler loads the symbol addresses with the "larl" instruction. This instruction sets the last bit to 0 and, therefore, for odd size files, the calculated size is one byte less than it should be: 0000000000540a9c <populate_rootfs>: 540a9c: eb cf f0 78 00 24 stmg %r12,%r15,120(%r15), 540aa2: c0 10 00 01 8a af larl %r1,572000 <__initramfs_start> 540aa8: c0 c0 00 03 e1 2e larl %r12,5bcd04 <initramfs_end> (Instead of 5bcd05) ... 540abe: 1b c1 sr %r12,%r1 To fix the problem, this patch introduces the global variable __initramfs_size, which is calculated in the "usr/initramfs_data.S" file. The populate_rootfs() function can then use the start marker of the .init.ramfs section and the value of __initramfs_size for loading the initramfs. Because the start marker and size is sufficient, the __initramfs_end symbol is no longer needed and is removed. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz> diff ffe8018c Fri Sep 17 16:24:11 MDT 2010 Hendrik Brueckner <brueckner@linux.vnet.ibm.com> initramfs: fix initramfs size calculation The size of a built-in initramfs is calculated in init/initramfs.c by "__initramfs_end - __initramfs_start". Those symbols are defined in the linker script include/asm-generic/vmlinux.lds.h: #define INIT_RAM_FS \ . = ALIGN(PAGE_SIZE); \ VMLINUX_SYMBOL(__initramfs_start) = .; \ *(.init.ramfs) \ VMLINUX_SYMBOL(__initramfs_end) = .; If the initramfs file has an odd number of bytes, the "__initramfs_end" symbol points to an odd address, for example, the symbols in the System.map might look like: 0000000000572000 T __initramfs_start 00000000005bcd05 T __initramfs_end <-- odd address At least on s390 this causes a problem: Certain s390 instructions, especially instructions for loading addresses (larl) or branch addresses must be on even addresses. The compiler loads the symbol addresses with the "larl" instruction. This instruction sets the last bit to 0 and, therefore, for odd size files, the calculated size is one byte less than it should be: 0000000000540a9c <populate_rootfs>: 540a9c: eb cf f0 78 00 24 stmg %r12,%r15,120(%r15), 540aa2: c0 10 00 01 8a af larl %r1,572000 <__initramfs_start> 540aa8: c0 c0 00 03 e1 2e larl %r12,5bcd04 <initramfs_end> (Instead of 5bcd05) ... 540abe: 1b c1 sr %r12,%r1 To fix the problem, this patch introduces the global variable __initramfs_size, which is calculated in the "usr/initramfs_data.S" file. The populate_rootfs() function can then use the start marker of the .init.ramfs section and the value of __initramfs_size for loading the initramfs. Because the start marker and size is sufficient, the __initramfs_end symbol is no longer needed and is removed. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz> diff ffe8018c Fri Sep 17 16:24:11 MDT 2010 Hendrik Brueckner <brueckner@linux.vnet.ibm.com> initramfs: fix initramfs size calculation The size of a built-in initramfs is calculated in init/initramfs.c by "__initramfs_end - __initramfs_start". Those symbols are defined in the linker script include/asm-generic/vmlinux.lds.h: #define INIT_RAM_FS \ . = ALIGN(PAGE_SIZE); \ VMLINUX_SYMBOL(__initramfs_start) = .; \ *(.init.ramfs) \ VMLINUX_SYMBOL(__initramfs_end) = .; If the initramfs file has an odd number of bytes, the "__initramfs_end" symbol points to an odd address, for example, the symbols in the System.map might look like: 0000000000572000 T __initramfs_start 00000000005bcd05 T __initramfs_end <-- odd address At least on s390 this causes a problem: Certain s390 instructions, especially instructions for loading addresses (larl) or branch addresses must be on even addresses. The compiler loads the symbol addresses with the "larl" instruction. This instruction sets the last bit to 0 and, therefore, for odd size files, the calculated size is one byte less than it should be: 0000000000540a9c <populate_rootfs>: 540a9c: eb cf f0 78 00 24 stmg %r12,%r15,120(%r15), 540aa2: c0 10 00 01 8a af larl %r1,572000 <__initramfs_start> 540aa8: c0 c0 00 03 e1 2e larl %r12,5bcd04 <initramfs_end> (Instead of 5bcd05) ... 540abe: 1b c1 sr %r12,%r1 To fix the problem, this patch introduces the global variable __initramfs_size, which is calculated in the "usr/initramfs_data.S" file. The populate_rootfs() function can then use the start marker of the .init.ramfs section and the value of __initramfs_size for loading the initramfs. Because the start marker and size is sufficient, the __initramfs_end symbol is no longer needed and is removed. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Michal Marek <mmarek@suse.cz> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Marek <mmarek@suse.cz> |
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