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linux/arch/parisc/include/asm
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Linus Torvalds 1bfa8bc86c work around gcc bugs with 'asm goto' with outputs 
commit 4356e9f841 upstream.

We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c323 ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").

Then, much later, we ended up removing the workaround in commit
43c249ea0b ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.

Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround.  But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.

It looks like there are at least two separate issues that all hit in
this area:

 (a) some versions of gcc don't mark the asm goto as 'volatile' when it
     has outputs:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420

     which is easy to work around by just adding the 'volatile' by hand.

 (b) Internal compiler errors:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422

     which are worked around by adding the extra empty 'asm' as a
     barrier, as in the original workaround.

but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.

but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.

Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-02-23 09:51:20 +01:00
..
alternative.h parisc: Mark altinstructions read-only and 32-bit aligned 2023-11-25 09:43:17 +01:00
asm-offsets.h kbuild: move asm-offsets.h to include/generated 2009-12-12 13:08:14 +01:00
asmregs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153 2019-05-30 11:26:32 -07:00
assembly.h parisc: Mark ex_table entries 32-bit aligned in assembly.h 2023-11-25 09:43:17 +01:00
atomic.h locking/atomic: parisc: add preprocessor symbols 2023-06-05 09:57:16 +02:00
barrier.h parisc: Add alternative patching to synchronize_caches define 2020-10-15 08:10:38 +02:00
bitops.h Revert "parisc: Show error if wrong 32/64-bit compiler is being used" 2022-08-22 11:09:17 +02:00
bug.h parisc: Fix asm operand number out of range build error in bug table 2023-11-27 11:01:38 +01:00
cache.h parisc: BTLB: Initialize BTLB tables at CPU startup 2023-09-07 09:12:20 +02:00
cacheflush.h mm: Introduce flush_cache_vmap_early() 2024-02-16 19:14:25 +01:00
checksum.h saner calling conventions for csum_and_copy_..._user() 2020-08-20 15:45:15 -04:00
cmpxchg.h locking/arch: Rename all internal __xchg() names to __arch_xchg() 2023-04-29 09:08:44 +02:00
compat.h asm-generic: compat: Cleanup duplicate definitions 2022-04-26 13:35:54 -07:00
compat_ucontext.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
current.h parisc: Reduce code size by optimizing get_current() function calls 2022-03-11 19:49:31 +01:00
delay.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dma-mapping.h dma-mapping: no need to pass a bus_type into get_arch_dma_ops() 2023-02-15 12:35:20 +01:00
dma.h parisc: dma: Add prototype for pcxl_dma_start 2023-08-10 19:12:16 +02:00
dwarf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
eisa_bus.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
eisa_eeprom.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
elf.h parisc: fix mmap_base calculation when stack grows upwards 2023-11-15 15:30:09 -08:00
fb.h arch/parisc: Implement <asm/fb.h> with generic helpers 2023-04-20 10:05:01 +02:00
fixmap.h parisc: Don't hardcode assembler bit definitions in tmpalias code 2022-05-23 13:44:24 +02:00
floppy.h arch/*/: remove CONFIG_VIRT_TO_BUS 2022-06-28 13:20:21 +02:00
ftrace.h parisc: ftrace: Add declaration for ftrace_function_trampoline() 2023-08-10 22:51:54 +02:00
futex.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
grfioctl.h parisc: Drop HP-UX constants and structs from grfioctl.h 2023-05-03 17:43:26 +02:00
hardirq.h softirq: Move __ARCH_HAS_DO_SOFTIRQ to Kconfig 2021-02-10 23:34:16 +01:00
hardware.h parisc: Avoid printing the hardware path twice 2022-10-31 15:37:14 +01:00
hash.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hugetlb.h mm: hugetlb: add huge page size param to set_huge_pte_at() 2023-09-29 17:20:47 -07:00
io.h parisc: mm: convert to GENERIC_IOREMAP 2023-08-18 10:12:35 -07:00
irq.h parisc: Remove leftover reference to the power_tasklet 2021-01-26 19:57:26 +01:00
irqflags.h parisc: Check if IRQs are disabled when calling arch_local_irq_restore() 2023-06-30 17:14:13 +02:00
jump_label.h work around gcc bugs with 'asm goto' with outputs 2024-02-23 09:51:20 +01:00
kbdleds.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kbuild char/agp: introduce asm-generic/agp.h 2023-02-13 22:13:29 +01:00
kexec.h parisc: fix compilation when KEXEC=n and KEXEC_FILE=y 2019-12-15 21:05:38 +01:00
kfence.h parisc: Add KFENCE support 2021-10-30 23:11:00 +02:00
kgdb.h parisc: Limit amount of kgdb breakpoints on parisc 2023-05-03 17:41:21 +02:00
kprobes.h parisc: Avoid using hardware single-step in kprobes 2022-03-18 09:10:14 +01:00
ldcw.h parisc: Mark lock_aligned variables 16-byte aligned on SMP 2023-11-25 09:43:17 +01:00
led.h parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem 2023-08-28 17:58:14 +02:00
linkage.h parisc: Fix boot failure of 64-bit kernel 2018-08-21 14:32:44 +02:00
mmu.h parisc: Add vDSO support 2022-03-11 19:49:30 +01:00
mmu_context.h parisc: Use constants to encode the space registers like SR_KERNEL 2022-03-11 19:49:31 +01:00
mmzone.h parisc: Switch from DISCONTIGMEM to SPARSEMEM 2019-05-03 23:47:40 +02:00
module.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page.h mm, arch: add generic implementation of pfn_valid() for FLATMEM 2023-02-09 16:51:41 -08:00
parisc-device.h parisc: Make struct parisc_driver::remove() return void 2021-08-30 10:18:25 +02:00
parport.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
patch.h parisc: add support for patching multiple words 2019-06-08 12:56:25 +02:00
pci.h PCI: Remove pci_get_legacy_ide_irq() and asm-generic/pci.h 2022-07-22 17:23:45 -05:00
pdc.h parisc: firmware: Simplify calling non-PA20 functions 2023-09-07 09:12:20 +02:00
pdc_chassis.h treewide: remove editor modelines and cruft 2021-05-07 00:26:34 -07:00
pdcpat.h parisc: Add PDC locking functions for rendezvous code 2022-03-29 21:37:12 +02:00
perf.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf_event.h irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
pgalloc.h parisc: rename PGD_ORDER to PGD_TABLE_ORDER 2022-07-17 17:14:43 -07:00
pgtable.h Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
prefetch.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
processor.h parisc: fix mmap_base calculation when stack grows upwards 2023-11-15 15:30:09 -08:00
psw.h parisc: asm: psw.h: missing header guard 2019-06-25 14:52:26 +02:00
ptrace.h parisc: Use PRIV_USER and PRIV_KERNEL in ptrace.h 2021-11-01 07:36:00 +01:00
ropes.h parisc: sba-iommu: Fix sparse warnigs 2023-08-31 21:42:42 +02:00
rt_sigframe.h parisc: Add vDSO support 2022-03-11 19:49:30 +01:00
runway.h parisc: ccio-dma: Create private runway procfs root entry 2023-08-28 18:00:27 +02:00
seccomp.h parisc: Enable seccomp architecture tracking 2020-11-20 11:16:34 -08:00
sections.h asm-generic: Refactor dereference_[kernel]_function_descriptor() 2022-02-16 23:25:11 +11:00
serial.h parisc: remove empty SERIAL_PORT_DFNS in serial.h 2013-11-30 21:02:18 +01:00
shmparam.h parisc: shmparam.h: Document aliasing requirements of PA-RISC 2023-09-07 08:00:32 +02:00
signal.h signal/parisc: Remove parisc specific definition of __ARCH_UAPI_SA_FLAGS 2020-11-30 13:43:35 -06:00
smp.h parisc: Implement __cpu_die() and __cpu_disable() for CPU hotplugging 2022-03-29 21:37:12 +02:00
socket.h parisc: Define O_NONBLOCK to become 000200000 2020-10-15 08:10:38 +02:00
sparsemem.h parisc: Switch from DISCONTIGMEM to SPARSEMEM 2019-05-03 23:47:40 +02:00
special_insns.h parisc: Add constants for control registers and clean up mfctl() 2022-03-29 21:37:12 +02:00
spinlock.h parisc: Fix lightweight spinlock checks to not break futexes 2023-08-10 17:32:09 +02:00
spinlock_types.h parisc: Restore __ldcw_align for PA-RISC 2.0 processors 2023-10-07 20:30:16 +02:00
string.h Revert "parisc: Add assembly implementations for memset, strlen, strcpy, strncpy and strcat" 2021-08-29 10:13:32 -07:00
superio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
switch_to.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
syscall.h parisc: define syscall_get_error() 2019-07-16 19:23:24 -07:00
thread_info.h parisc: move CPU field back into thread_info 2021-11-04 11:21:47 +01:00
timex.h parisc: define get_cycles macro for arch-override 2022-05-13 23:59:23 +02:00
tlb.h parisc: use pgtable-nopXd instead of 4level-fixup 2019-12-04 19:44:15 -08:00
tlbflush.h parisc: Add vDSO support 2022-03-11 19:49:30 +01:00
topology.h parisc: Switch from GENERIC_CPU_DEVICES to GENERIC_ARCH_TOPOLOGY 2022-03-29 21:37:12 +02:00
traps.h parisc: Fix handling off probe non-access faults 2022-03-11 19:49:30 +01:00
uaccess.h parisc: Mark ex_table entries 32-bit aligned in uaccess.h 2023-11-25 09:43:17 +01:00
ucontext.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
unaligned.h parisc: Drop ifdef __KERNEL__ from non-uapi kernel headers 2021-11-01 07:36:00 +01:00
unistd.h RISC-V Patches for the 5.19 Merge Window, Part 1 2022-05-31 14:10:54 -07:00
unwind.h parisc: Consolidate unwind initialization calls 2018-08-17 17:00:08 +02:00
vdso.h parisc: Add vDSO support 2022-03-11 19:49:30 +01:00
vmalloc.h mm/vmalloc: Add empty <asm/vmalloc.h> headers and use them from <linux/vmalloc.h> 2019-12-10 10:12:55 +01:00