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H A D | head.S | diff e9953b72 Wed May 11 06:05:30 MDT 2022 Heiko Carstens <hca@linux.ibm.com> s390/boot: workaround llvm IAS bug For at least the mvc and clc instructions llvm's integrated assembler can generate incorrect code. In particular this happens with decompressor boot code. The reason seems to be that relocations for the second displacement of each instruction are at incorrect locations (-/+: gas vs llvm IAS): mvc __LC_IO_NEW_PSW(16),.Lnewpsw results in 4: d2 0f 01 f0 00 00 mvc 496(16,%r0),0 - 8: R_390_12 .head.text+0x10 + 6: R_390_12 .head.text+0x10 and clc 0(3,%r4),.L_hdr results in 258: d5 02 40 00 00 00 clc 0(3,%r4),0 - 25c: R_390_12 .head.text+0x324 + 25a: R_390_12 .head.text+0x324 Workaround this by writing the code in a different way. Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://github.com/llvm/llvm-project/issues/55411 Link: https://lore.kernel.org/r/20220511120532.2228616-7-hca@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 8b6bd6f2 Tue Jun 15 07:59:32 MDT 2021 Alexander Egorenkov <egorenar@linux.ibm.com> s390/boot: get rid of magic numbers for startup offsets Use STARTUP_NORMAL_OFFSET and STARTUP_KDUMP_OFFSET instead of magic numbers. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> diff 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> diff 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> diff 8e5a7627 Wed Sep 12 00:54:59 MDT 2018 Martin Schwidefsky <schwidefsky@de.ibm.com> s390: add initial 64-bit restart PSW To be able to start a kernel image loaded into memory with a PSW restart, place a 64-bit restart PSW at 0x1a0 in absolute lowcore. Suggested-by: Dominik Klein <dominik.klein@linux.ibm.com> Tested-by: Dominik Klein <dominik.klein@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
H A D | boot.h | diff 8c37cb7d Wed Feb 08 10:11:25 MST 2023 Vasily Gorbik <gor@linux.ibm.com> s390/boot: rename mem_detect to physmem_info In preparation to extending mem_detect with additional information like reserved ranges rename it to more generic physmem_info. This new naming also help to avoid confusion by using more exact terms like "physmem online ranges", etc. Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
H A D | startup.c | diff 8d5e98f8 Mon Sep 11 13:39:58 MDT 2023 Heiko Carstens <hca@linux.ibm.com> s390/ctlreg: add local and system prefix to some functions Add local and system prefix to some functions to clarify they change control register contents on either the local CPU or the on all CPUs. This results in the following API: Two defines which load and save multiple control registers. The defines correlate with the following C prototypes: void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high); void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high); Two functions which locally set or clear one bit for a specified control register: void local_ctl_set_bit(unsigned int cr, unsigned int bit); void local_ctl_clear_bit(unsigned int cr, unsigned int bit); Two functions which set or clear one bit for a specified control register on all CPUs: void system_ctl_set_bit(unsigned int cr, unsigned int bit); void system_ctl_clear_bit(unsigend int cr, unsigned int bit); Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> diff 8ddccc8a Wed Jul 05 16:28:17 MDT 2023 Alexander Gordeev <agordeev@linux.ibm.com> s390/boot: cleanup number of page table levels setup The separate vmalloc area size check against _REGION2_SIZE is needed in case user provided insanely large value using vmalloc= kernel command line parameter. That could lead to overflow and selecting 3 page table levels instead of 4. Use size_add() for the overflow check and get rid of the extra vmalloc area check. With the current values of CONFIG_MAX_PHYSMEM_BITS and PAGES_PER_SECTION the sum of maximal possible size of identity mapping and vmemmap area (derived from these macros) plus modules area size MODULES_LEN can not overflow. Thus, that sum is used as first addend while vmalloc area size is second addend for size_add(). Suggested-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 8c37cb7d Wed Feb 08 10:11:25 MST 2023 Vasily Gorbik <gor@linux.ibm.com> s390/boot: rename mem_detect to physmem_info In preparation to extending mem_detect with additional information like reserved ranges rename it to more generic physmem_info. This new naming also help to avoid confusion by using more exact terms like "physmem online ranges", etc. Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 8e9205d2 Sun Dec 11 00:18:57 MST 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/mm: allocate Real Memory Copy Area in decompressor Move Real Memory Copy Area allocation to the decompressor. As result, memcpy_real() and memcpy_real_iter() movers become usable since the very moment the kernel starts. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 4df29d2b Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> diff 4df29d2b Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> diff 4df29d2b Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> diff 7d06fed7 Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> diff 7d06fed7 Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> diff 7d06fed7 Wed Jul 20 00:22:01 MDT 2022 Alexander Gordeev <agordeev@linux.ibm.com> s390/smp: rework absolute lowcore access Temporary unsetting of the prefix page in memcpy_absolute() routine poses a risk of executing code path with unexpectedly disabled prefix page. This rework avoids the prefix page uninstalling and disabling of normal and machine check interrupts when accessing the absolute zero memory. Although memcpy_absolute() routine can access the whole memory, it is only used to update the absolute zero lowcore. This rework therefore introduces a new mechanism for the absolute zero lowcore access and scraps memcpy_absolute() routine for good. Instead, an area is reserved in the virtual memory that is used for the absolute lowcore access only. That area holds an array of 8KB virtual mappings - one per CPU. Whenever a CPU is brought online, the corresponding item is mapped to the real address of the previously installed prefix page. The absolute zero lowcore access works like this: a CPU calls the new primitive get_abs_lowcore() to obtain its 8KB mapping as a pointer to the struct lowcore. Virtual address references to that pointer get translated to the real addresses of the prefix page, which in turn gets swapped with the absolute zero memory addresses due to prefixing. Once the pointer is not needed it must be released with put_abs_lowcore() primitive: struct lowcore *abs_lc; unsigned long flags; abs_lc = get_abs_lowcore(&flags); abs_lc->... = ...; put_abs_lowcore(abs_lc, flags); To ensure the described mechanism works large segment- and region- table entries must be avoided for the 8KB mappings. Failure to do so results in usage of Region-Frame Absolute Address (RFAA) or Segment-Frame Absolute Address (SFAA) large page fields. In that case absolute addresses would be used to address the prefix page instead of the real ones and the prefixing would get bypassed. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> |
H A D | Makefile | diff 9ea30fd1 Fri Feb 16 00:55:53 MST 2024 Nathan Chancellor <nathan@kernel.org> s390/boot: add 'alloc' to info.bin .vmlinux.info section flags When attempting to boot a kernel compiled with OBJCOPY=llvm-objcopy, there is a crash right at boot: Out of memory allocating 6d7800 bytes 8 aligned in range 0:20000000 Reserved memory ranges: 0000000000000000 a394c3c30d90cdaf DECOMPRESSOR Usable online memory ranges (info source: sclp read info [3]): 0000000000000000 0000000020000000 Usable online memory total: 20000000 Reserved: a394c3c30d90cdaf Free: 0 Call Trace: (sp:0000000000033e90 [<0000000000012fbc>] physmem_alloc_top_down+0x5c/0x104) sp:0000000000033f00 [<0000000000011d56>] startup_kernel+0x3a6/0x77c sp:0000000000033f60 [<00000000000100f4>] startup_normal+0xd4/0xd4 GNU objcopy does not have any issues. Looking at differences between the object files in each build reveals info.bin does not get properly populated with llvm-objcopy, which results in an empty .vmlinux.info section. $ file {gnu,llvm}-objcopy/arch/s390/boot/info.bin gnu-objcopy/arch/s390/boot/info.bin: data llvm-objcopy/arch/s390/boot/info.bin: empty $ llvm-readelf --section-headers {gnu,llvm}-objcopy/arch/s390/boot/vmlinux | rg 'File:|\.vmlinux\.info|\.decompressor\.syms' File: gnu-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 File: llvm-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000000 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034000 035000 000b00 00 WA 0 0 1 Ulrich points out that llvm-objcopy only copies sections marked as alloc with a binary output target, whereas the .vmlinux.info section is only marked as load. Add 'alloc' in addition to 'load', so that both objcopy implementations work properly: $ file {gnu,llvm}-objcopy/arch/s390/boot/info.bin gnu-objcopy/arch/s390/boot/info.bin: data llvm-objcopy/arch/s390/boot/info.bin: data $ llvm-readelf --section-headers {gnu,llvm}-objcopy/arch/s390/boot/vmlinux | rg 'File:|\.vmlinux\.info|\.decompressor\.syms' File: gnu-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 File: llvm-objcopy/arch/s390/boot/vmlinux [12] .vmlinux.info PROGBITS 0000000000034000 035000 000078 00 WA 0 0 1 [13] .decompressor.syms PROGBITS 0000000000034078 035078 000b00 00 WA 0 0 1 Closes: https://github.com/ClangBuiltLinux/linux/issues/1996 Link: https://github.com/llvm/llvm-project/commit/3c02cb7492fc78fb678264cebf57ff88e478e14f Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20240216-s390-fix-boot-with-llvm-objcopy-v1-1-0ac623daf42b@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 2151fd9a Wed Feb 07 17:14:53 MST 2024 Nathan Chancellor <nathan@kernel.org> s390/boot: add support for CONFIG_LD_ORPHAN_WARN arch/s390/boot/vmlinux uses a different linker script and build rules than the main vmlinux, so the '--orphan-handling' flag is not applied to it. Add support for '--orphan-handling' so that all sections are properly described in the linker script, which helps eliminate bugs between linker implementations having different orphan section heuristics. Signed-off-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Justin Stitt <justinstitt@google.com> Link: https://lore.kernel.org/r/20240207-s390-lld-and-orphan-warn-v1-1-8a665b3346ab@kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 8c37cb7d Wed Feb 08 10:11:25 MST 2023 Vasily Gorbik <gor@linux.ibm.com> s390/boot: rename mem_detect to physmem_info In preparation to extending mem_detect with additional information like reserved ranges rename it to more generic physmem_info. This new naming also help to avoid confusion by using more exact terms like "physmem online ranges", etc. Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> diff 6abe2819 Mon Jul 15 07:30:33 MDT 2019 Vasily Gorbik <gor@linux.ibm.com> s390: enable detection of kernel version from bzImage Extend "parmarea" to include an offset of the version string, which is stored as 8-byte big endian value. To retrieve version string from bzImage reliably, one should check the presence of "S390EP" ascii string at 0x10008 (available since v3.2), then read the version string offset from 0x10428 (which has been 0 since v3.2 up to now). The string is null terminated. Could be retrieved with the following "file" command magic (requires file v5.34): 8 string \x02\x00\x00\x18\x60\x00\x00\x50\x02\x00\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40\x40\x40\x40\x40 Linux S390 >0x10008 string S390EP >>0x10428 bequad >0 >>>(0x10428.Q) string >\0 \b, version %s Reported-by: Petr Tesarik <ptesarik@suse.com> Suggested-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> diff 8db16d19 Tue May 07 05:56:45 MDT 2019 Martin Schwidefsky <schwidefsky@de.ibm.com> s390/boot: fix compiler error due to missing awk strtonum The strtonum awk function is a GNU extension and is not available with all versions of awk. The link of bzImage fails with this error message: >> awk: line 2: function or never defined >> awk: line 2: function strtonum never defined objcopy: --pad-to: bad number: arch/s390/boot/compressed/vmlinux Drop the awk script and the --pad-to objcopy parameter it generated and use a FILL pattern with an appropriate alignment in the linker script for the arch/s390/boot/compressed/vmlinux file. Fixes: f6780686525c ("s390/boot: pad bzImage to 4K") Reported-by: kbuild test robot <lkp@intel.com> Suggested-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> diff 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> diff 8f75582a Thu Jul 19 05:11:28 MDT 2018 Vasily Gorbik <gor@linux.ibm.com> s390: remove decompressor's head.S Decompressor's head.S provided "data mover" sole purpose of which has been to safely move uncompressed kernel at 0x100000 and jump to it. With current bzImage layout entire decompressor's code guaranteed to be in a safe location under 0x100000, and hence could not be overwritten during kernel move. For that reason head.S could be replaced with simple memmove function. To do so introduce early boot code phase which is executed from arch/s390/boot/head.S after "verify_facilities" and takes care of optional kernel image decompression and transition to it. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
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