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[PATCH 5.15.y] s390/entry: Fix last breaking event handling in case of stack corruption

by Heiko Carstens

commit ae952eea6f4a7e2193f8721a5366049946e012e7 upstream. Note: the GET_LC macro and all the infrastructe that comes with this does not exist for this kernel release. Therefore the patch is slightly different to the upstream variant. In case of stack corruption stack_invalid() is called and the expectation is that register r10 contains the last breaking event address. This dependency is quite subtle and broke a couple of years ago without that anybody noticed. Fix this by getting rid of the dependency and read the last breaking event address from lowcore. Fixes: 56e62a737028 ("s390: convert to generic entry") Acked-by: Ilya Leoshkevich <iii(a)linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> --- arch/s390/kernel/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 160290049e8c..14a5eff4d027 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -676,7 +676,7 @@ ENTRY(stack_overflow) stmg %r0,%r7,__PT_R0(%r11) stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_R8(64,%r11),0(%r14) - stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2 + mvc __PT_ORIG_GPR2(8,%r11),__LC_LAST_BREAK xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs jg kernel_stack_overflow -- 2.48.1

2 weeks, 6 days

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Re: [PATCH 2/2] f2fs: sysfs: export linear_lookup in features directory

by Sasha Levin

[ Sasha's backport helper bot ] Hi, Summary of potential issues: ℹ️ This is part 2/2 of a series ⚠️ Found matching upstream commit but patch is missing proper reference to it Found matching upstream commit: 617e0491abe4d8d45c5110ca474c0feb428e6828 Note: The patch differs from the upstream commit: --- 1: 617e0491abe4d ! 1: 4c702e18f9b37 f2fs: sysfs: export linear_lookup in features directory @@ Commit message supported Signed-off-by: Chao Yu <chao(a)kernel.org> - Signed-off-by: Jaegeuk Kim <jaegeuk(a)kernel.org> ## Documentation/ABI/testing/sysfs-fs-f2fs ## @@ Documentation/ABI/testing/sysfs-fs-f2fs: Description: Shows all enabled kernel features. --- NOTE: These results are for this patch alone. Full series testing will be performed when all parts are received. Results of testing on various branches: | Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-5.4.y | Success | Success |

2 weeks, 6 days

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[PATCH v2 6.6.y 0/2] Kunit to check the longest symbol length

by Sergio González Collado

Hello, Please consider this series for 6.6.y This patch series backports two patches that implement a test to verify that a symbol with KSYM_NAME_LEN of 512 can be read. The first patch implements the test. This commit also includes a fix for the test x86/insn_decoder_test. In the case a symbol exceeds the symbol length limit, an error will happen: arch/x86/tools/insn_decoder_test: error: malformed line 1152000: tBb_+0xf2> ..which overflowed by 10 characters reading this line: ffffffff81458193: 74 3d je ffffffff814581d2 <_RNvXse_NtNtNtCshGpAVYOtgW1_4core4iter8adapters7flattenINtB5_13FlattenCompatINtNtB7_3map3MapNtNtNtBb_3str4iter5CharsNtB1v_17CharEscapeDefaultENtNtBb_4char13EscapeDefaultENtNtBb_3fmt5Debug3fmtBb_+0xf2> The fix was proposed in [1] and initially mentioned at [2]. The second patch fixes a warning when building with clang because there was a definition of unlikely from compiler.h in tools/include/linux, which conflicted with the one in the instruction decoder selftest. [1] https://lore.kernel.org/lkml/Y9ES4UKl%2F+DtvAVS@gmail.com/ [2] https://lore.kernel.org/lkml/320c4dba-9919-404b-8a26-a8af16be1845@app.fastm… Signed-off-by: Sergio González Collado <sergio.collado(a)gmail.com> --- Changes in v2: sign-off patch 2/2 --- Nathan Chancellor (1): x86/tools: Drop duplicate unlikely() definition in insn_decoder_test.c Sergio González Collado (1): Kunit to check the longest symbol length arch/x86/tools/insn_decoder_test.c | 5 +- lib/Kconfig.debug | 9 ++++ lib/Makefile | 2 + lib/longest_symbol_kunit.c | 82 ++++++++++++++++++++++++++++++ 4 files changed, 95 insertions(+), 3 deletions(-) create mode 100644 lib/longest_symbol_kunit.c base-commit: 6282921b6825fef6a1243e1c80063421d41e2576 -- 2.39.2

2 weeks, 6 days

3
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[PATCH 5.10.y] s390: Add '-std=gnu11' to decompressor and purgatory CFLAGS

by Heiko Carstens

From: Nathan Chancellor <nathan(a)kernel.org> commit 3b8b80e993766dc96d1a1c01c62f5d15fafc79b9 upstream. GCC changed the default C standard dialect from gnu17 to gnu23, which should not have impacted the kernel because it explicitly requests the gnu11 standard in the main Makefile. However, there are certain places in the s390 code that use their own CFLAGS without a '-std=' value, which break with this dialect change because of the kernel's own definitions of bool, false, and true conflicting with the C23 reserved keywords. include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant 11 | false = 0, | ^~~~~ include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef' 35 | typedef _Bool bool; | ^~~~ include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate these errors and make the C standard version of these areas match the rest of the kernel. Cc: stable(a)vger.kernel.org Signed-off-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Heiko Carstens <hca(a)linux.ibm.com> Link: https://lore.kernel.org/r/20250122-s390-fix-std-for-gcc-15-v1-1-8b00cadee08… Signed-off-by: Alexander Gordeev <agordeev(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> --- arch/s390/Makefile | 2 +- arch/s390/purgatory/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/Makefile b/arch/s390/Makefile index 39ffcd4389f1..92f2426d8797 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -23,7 +23,7 @@ endif aflags_dwarf := -Wa,-gdwarf-2 KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__ KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf)) -KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 +KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -std=gnu11 KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile index a93c9aba834b..955f113cf320 100644 --- a/arch/s390/purgatory/Makefile +++ b/arch/s390/purgatory/Makefile @@ -20,7 +20,7 @@ GCOV_PROFILE := n UBSAN_SANITIZE := n KASAN_SANITIZE := n -KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes +KBUILD_CFLAGS := -std=gnu11 -fno-strict-aliasing -Wall -Wstrict-prototypes KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding KBUILD_CFLAGS += -c -MD -Os -m64 -msoft-float -fno-common -- 2.48.1

2 weeks, 6 days

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FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062021-owl-bauble-35cd@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
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FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062022-gracious-throttle-46c8@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
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FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062020-aware-estranged-e8a8@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
2
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FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062023-wobbling-aloof-8d23@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
2
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FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062020-kindness-glancing-e58b@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
2
0 0

FAILED: patch "[PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x c4abe6234246c75cdc43326415d9cff88b7cf06c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025062021-coastline-bacteria-9de3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c4abe6234246c75cdc43326415d9cff88b7cf06c Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca(a)linux.ibm.com> Date: Mon, 19 May 2025 18:07:11 +0200 Subject: [PATCH] s390/pci: Fix __pcilg_mio_inuser() inline assembly Use "a" constraint for the shift operand of the __pcilg_mio_inuser() inline assembly. The used "d" constraint allows the compiler to use any general purpose register for the shift operand, including register zero. If register zero is used this my result in incorrect code generation: 8f6: a7 0a ff f8 ahi %r0,-8 8fa: eb 32 00 00 00 0c srlg %r3,%r2,0 <---- If register zero is selected to contain the shift value, the srlg instruction ignores the contents of the register and always shifts zero bits. Therefore use the "a" constraint which does not permit to select register zero. Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO") Cc: stable(a)vger.kernel.org Reported-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle(a)linux.ibm.com> Signed-off-by: Heiko Carstens <hca(a)linux.ibm.com> diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 9680055edb78..51e7a28af899 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -244,7 +244,7 @@ static inline int __pcilg_mio_inuser( : [ioaddr_len] "+&d" (ioaddr_len.pair), [exc] "+d" (exception), CC_OUT(cc, cc), [val] "=d" (val), [dst] "+a" (dst), [cnt] "+d" (cnt), [tmp] "=d" (tmp), - [shift] "+d" (shift) + [shift] "+a" (shift) : : CC_CLOBBER_LIST("memory")); disable_sacf_uaccess(sacf_flag);

2 weeks, 6 days

3
2
0 0

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