linux-stable/arch/powerpc/kernel
Michael Ellerman a88603f4b9 powerpc/vdso: Don't use r30 to avoid breaking Go lang
The Go runtime uses r30 for some special value called 'g'. It assumes
that value will remain unchanged even when calling VDSO functions.
Although r30 is non-volatile across function calls, the callee is free
to use it, as long as the callee saves the value and restores it before
returning.

It used to be true by accident that the VDSO didn't use r30, because the
VDSO was hand-written asm. When we switched to building the VDSO from C
the compiler started using r30, at least in some builds, leading to
crashes in Go. eg:

  ~/go/src$ ./all.bash
  Building Go cmd/dist using /usr/lib/go-1.16. (go1.16.2 linux/ppc64le)
  Building Go toolchain1 using /usr/lib/go-1.16.
  go build os/exec: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go build reflect: /usr/lib/go-1.16/pkg/tool/linux_ppc64le/compile: signal: segmentation fault
  go tool dist: FAILED: /usr/lib/go-1.16/bin/go install -gcflags=-l -tags=math_big_pure_go compiler_bootstrap bootstrap/cmd/...: exit status 1

There are patches in flight to fix Go[1], but until they are released
and widely deployed we can workaround it in the VDSO by avoiding use of
r30.

Note this only works with GCC, clang does not support -ffixed-rN.

1: https://go-review.googlesource.com/c/go/+/328110

Fixes: ab037dd87a ("powerpc/vdso: Switch VDSO to generic C implementation.")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210729131244.2595519-1-mpe@ellerman.id.au
2021-07-29 23:13:12 +10:00
..
ptrace powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
syscalls quota: Wire up quotactl_fd syscall 2021-06-07 12:11:24 +02:00
trace powerpc: Don't use 'struct ppc_inst' to reference instruction location 2021-06-17 00:09:00 +10:00
vdso32 powerpc updates for 5.13 2021-04-30 12:22:28 -07:00
vdso64 powerpc/vdso: Don't use r30 to avoid breaking Go lang 2021-07-29 23:13:12 +10:00
.gitignore
align.c powerpc: Rename probe_kernel_read_inst() 2021-04-21 22:52:33 +10:00
asm-offsets.c powerpc/64: use interrupt restart table to speed up return from interrupt 2021-06-25 00:06:56 +10:00
audit.c
btext.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
cacheinfo.c powerpc/cacheinfo: Print correct cache-sibling map/list for L2 cache 2020-12-11 00:10:25 +11:00
cacheinfo.h
compat_audit.c
cpu_setup_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
cpu_setup_44x.S
cpu_setup_fsl_booke.S powerpc: Retire e200 core (mpc555x processor) 2020-12-05 21:49:18 +11:00
cpu_setup_pa6t.S
cpu_setup_power.c powerpc/perf: MMCR0 control for PMU registers under PMCC=00 2020-12-04 01:01:29 +11:00
cpu_setup_ppc970.S
cputable.c arch: powerpc: Stop building and using oprofile 2021-01-29 10:05:51 +05:30
crash_dump.c powerpc: Don't use 'struct ppc_inst' to reference instruction location 2021-06-17 00:09:00 +10:00
dawr.c powerpc/watchpoint: Guest support for 2nd DAWR hcall 2020-07-26 23:34:19 +10:00
dbell.c powerpc: handle irq_enter/irq_exit in interrupt handler wrappers 2021-02-09 00:10:49 +11:00
dma-iommu.c powerpc/dma: Fallback to dma_ops when persistent memory present 2020-11-27 10:33:42 +01:00
dma-mask.c
dma-swiotlb.c
dt_cpu_ftrs.c arch: powerpc: Stop building and using oprofile 2021-01-29 10:05:51 +05:30
early_32.c
eeh.c powerpc: Fix reverse map real-mode address lookup with huge vmalloc 2021-05-28 22:54:27 +10:00
eeh_cache.c powerpc/eeh_cache: Fix a possible debugfs deadlock 2020-11-02 12:54:20 +11:00
eeh_driver.c pci-v5.9-changes 2020-08-07 18:48:15 -07:00
eeh_event.c
eeh_pe.c powerpc/eeh: Delete eeh_pe->config_addr 2020-10-07 22:34:47 +11:00
eeh_sysfs.c powerpc/eeh: Pass eeh_dev to eeh_ops->resume_notify() 2020-07-26 23:34:20 +10:00
entry_32.S powerpc/32: Reduce code duplication of system call entry 2021-06-25 00:07:10 +10:00
entry_64.S powerpc/64: move interrupt return asm to interrupt_64.S 2021-06-25 00:06:55 +10:00
epapr_hcalls.S
epapr_paravirt.c powerpc: Don't use 'struct ppc_inst' to reference instruction location 2021-06-17 00:09:00 +10:00
exceptions-64e.S powerpc/64e: remove implicit soft-masking and interrupt exit restart logic 2021-06-30 22:21:20 +10:00
exceptions-64s.S powerpc/64s: add a table of implicit soft-masked addresses 2021-06-30 22:21:20 +10:00
fadump.c powerpc/fadump: Fix sparse warnings 2021-04-22 20:59:04 +10:00
firmware.c powerpc: Fix is_kvm_guest() / kvm_para_available() 2021-06-25 14:47:19 +10:00
fpu.S powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
fsl_booke_entry_mapping.S
head_8xx.S powerpc: Define swapper_pg_dir[] in C 2021-06-17 00:09:10 +10:00
head_32.h powerpc/32: Reduce code duplication of system call entry 2021-06-25 00:07:10 +10:00
head_40x.S powerpc: Define swapper_pg_dir[] in C 2021-06-17 00:09:10 +10:00
head_44x.S powerpc: Define swapper_pg_dir[] in C 2021-06-17 00:09:10 +10:00
head_64.S powerpc/64: move interrupt return asm to interrupt_64.S 2021-06-25 00:06:55 +10:00
head_book3s_32.S powerpc: Remove klimit 2021-06-25 00:07:10 +10:00
head_booke.h powerpc/32: Avoid #ifdef nested with FTR_SECTION on booke syscall entry 2021-06-25 00:07:11 +10:00
head_fsl_booke.S powerpc: Define swapper_pg_dir[] in C 2021-06-17 00:09:10 +10:00
hw_breakpoint.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
hw_breakpoint_constraints.c powerpc/uaccess: Remove __get/put_user_inatomic() 2021-04-03 21:21:41 +11:00
idle.c sched/idle: Fix arch_cpu_idle() vs tracing 2020-11-24 16:47:35 +01:00
idle_6xx.S powerpc/32: Return directly from power_save_ppc32_restore() 2021-03-29 13:22:10 +11:00
idle_book3e.S
idle_book3s.S powerpc/64s: power4 nap fixup in C 2021-04-08 21:17:45 +10:00
idle_e500.S powerpc/32: Return directly from power_save_ppc32_restore() 2021-03-29 13:22:10 +11:00
ima_arch.c
interrupt.c powerpc/64e: remove implicit soft-masking and interrupt exit restart logic 2021-06-30 22:21:20 +10:00
interrupt_64.S powerpc/64e: Fix system call illegal mtmsrd instruction 2021-07-06 19:58:54 +10:00
io-workarounds.c powerpc: Fix reverse map real-mode address lookup with huge vmalloc 2021-05-28 22:54:27 +10:00
io.c
iomap.c powerpc: inline iomap accessors 2020-12-04 01:01:09 +11:00
iommu.c Revert "powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs" 2021-06-01 11:17:08 +10:00
irq.c powerpc/64: enable MSR[EE] in irq replay pt_regs 2021-06-30 22:21:20 +10:00
isa-bridge.c mm/vmalloc: remove unmap_kernel_range 2021-04-30 11:20:40 -07:00
jump_label.c powerpc: Don't use 'struct ppc_inst' to reference instruction location 2021-06-17 00:09:00 +10:00
kgdb.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
kprobes-ftrace.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
kprobes.c powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
kvm.c
kvm_emul.S
l2cr_6xx.S powerpc: Drop SYNC_601() ISYNC_601() and SYNC() 2020-10-08 21:17:13 +11:00
legacy_serial.c powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds 2021-05-12 11:07:39 +10:00
Makefile powerpc/vdso: Make sure vdso_wrapper.o is rebuilt everytime vdso.so is rebuilt 2021-04-02 00:18:09 +11:00
mce.c powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
mce_power.c powerpc/powernv: Fix machine check reporting of async store errors 2021-06-21 21:13:19 +10:00
misc.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
misc_32.S powerpc/32: Remove __main() 2021-06-17 00:09:10 +10:00
misc_64.S powerpc/irq: Inline call_do_irq() and call_do_softirq() 2021-03-29 13:22:17 +11:00
module.c powerpc/modules: Make module_alloc() Strict Module RWX aware 2021-06-21 21:13:20 +10:00
module_32.c powerpc/modules: Use PPC_RAW_xx() macros 2021-06-16 00:16:48 +10:00
module_64.c powerpc/modules: Use PPC_RAW_xx() macros 2021-06-16 00:16:48 +10:00
msi.c
note.S
nvram_64.c printk: introduce a kmsg_dump iterator 2021-03-08 11:43:27 +01:00
of_platform.c powerpc/eeh: Remove eeh_dev_phb_init_dynamic() 2020-07-26 23:34:19 +10:00
optprobes.c powerpc/kprobes: Fix Oops by passing ppc_inst as a pointer to emulate_step() on ppc32 2021-06-25 14:46:51 +10:00
optprobes_head.S powerpc: Enable OPTPROBES on PPC32 2021-04-21 22:52:32 +10:00
paca.c powerpc/paca: Remove mm_ctx_id and mm_ctx_slb_addr_limit 2021-05-17 15:27:15 +10:00
pci-common.c powerpc/pci: Add ppc_md.discover_phbs() 2021-02-03 09:46:36 +11:00
pci-hotplug.c powerpc/eeh: Release EEH device state synchronously 2020-05-18 21:58:44 +10:00
pci_32.c
pci_64.c mm/vmalloc: remove unmap_kernel_range 2021-04-30 11:20:40 -07:00
pci_dn.c powerpc/pci: Move PHB discovery for PCI_DN using platforms 2021-02-09 00:01:05 +11:00
pci_of_scan.c
pmc.c
ppc32.h
ppc_save_regs.S
proc_powerpc.c
process.c powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
prom.c powerpc: Remove klimit 2021-06-25 00:07:10 +10:00
prom_init.c powerpc/64s: Make prom_init require RELOCATABLE 2021-06-25 14:47:19 +10:00
prom_init_check.sh
prom_parse.c
reloc_32.S
reloc_64.S
rtas-proc.c powerpc/rtas: rename RTAS_RMOBUF_MAX to RTAS_USER_REGION_SIZE 2021-04-14 23:04:16 +10:00
rtas-rtc.c powerpc/rtas-rtc: remove unused constant 2021-06-25 14:47:20 +10:00
rtas.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
rtas_flash.c
rtas_pci.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
rtasd.c powerpc/rtasd: simplify handle_rtas_event(), emit message on events 2020-07-16 13:12:38 +10:00
secure_boot.c powerpc/pseries: Detect secure and trusted boot state of the system. 2020-07-16 14:49:53 +10:00
security.c powerpc/security: Add a security feature for STF barrier 2021-06-21 21:13:19 +10:00
secvar-ops.c
secvar-sysfs.c
setup-common.c powerpc: convert to setup_initial_init_mm() 2021-07-08 11:48:21 -07:00
setup.h powerpc: remove unneeded semicolons 2021-02-09 00:10:50 +11:00
setup_32.c powerpc: Don't use 'struct ppc_inst' to reference instruction location 2021-06-17 00:09:00 +10:00
setup_64.c powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
signal.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
signal.h powerpc/signal: Fix possible build failure with unsafe_copy_fpr_{to/from}_user 2021-05-12 11:07:39 +10:00
signal_32.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
signal_64.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
smp-tbsync.c
smp.c powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
stacktrace.c powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() 2021-06-26 00:04:21 +10:00
suspend.c
swsusp.c
swsusp_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
swsusp_64.c
swsusp_asm64.S
swsusp_booke.S
sys_ppc32.c powerpc/compat_sys: swap hi/lo parts of 64-bit syscall args in LE mode 2021-02-11 23:35:07 +11:00
syscalls.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
sysfs.c powerpc/sysfs: Replace sizeof(arr)/sizeof(arr[0]) with ARRAY_SIZE 2021-06-26 00:13:27 +10:00
systbl.S powerpc/syscalls: switch to generic syscalltbl.sh 2021-04-14 23:04:16 +10:00
systbl_chk.sh
tau_6xx.c powerpc/tau: Remove superfluous parameter in alloc_workqueue() call 2021-06-15 23:47:10 +10:00
time.c powerpc/64s: Remove irq mask workaround in accumulate_stolen_time() 2021-06-25 00:07:09 +10:00
tm.S powerpc/tm: Save and restore AMR on treclaim and trechkpt 2020-10-06 23:22:25 +11:00
traps.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
ucall.S
udbg.c
udbg_16550.c powerpc/microwatt: Use standard 16550 UART for console 2021-06-21 21:16:31 +10:00
uprobes.c powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
vdso.c powerpc/vdso: Add support for time namespaces 2021-04-14 23:04:44 +10:00
vdso32_wrapper.S powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o 2021-01-30 22:23:42 +11:00
vdso64_wrapper.S powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o 2021-01-30 22:23:42 +11:00
vecemu.c powerpc: Define and use get_user_instr() et. al. 2020-05-19 00:10:37 +10:00
vector.S powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
vmlinux.lds.S powerpc/64s: add a table of implicit soft-masked addresses 2021-06-30 22:21:20 +10:00
watchdog.c powerpc/watchdog: include linux/processor.h for spin_until_cond 2021-06-17 00:09:12 +10:00