| Message ID | 20190301132809.24653-2-will.deacon@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Rework debug exception handling code | expand |
On Fri, Mar 01, 2019 at 01:28:00PM +0000, Will Deacon wrote: > FAR_EL1 is UNKNOWN for all debug exceptions other than those caused by > taking a hardware watchpoint. Unfortunately, if a debug handler returns > a non-zero value, then we will propagate the UNKNOWN FAR value to > userspace via the si_addr field of the SIGTRAP siginfo_t. > > Instead, let's set si_addr to take on the PC of the faulting instruction, > which we have available in the current pt_regs. > > Cc: <stable@vger.kernel.org> > Signed-off-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > arch/arm64/mm/fault.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index efb7b2cbead5..ef46925096f0 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -824,11 +824,12 @@ void __init hook_debug_fault_code(int nr, > debug_fault_info[nr].name = name; > } > > -asmlinkage int __exception do_debug_exception(unsigned long addr, > +asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint, > unsigned int esr, > struct pt_regs *regs) > { > const struct fault_info *inf = esr_to_debug_fault_info(esr); > + unsigned long pc = instruction_pointer(regs); > int rv; > > /* > @@ -838,14 +839,14 @@ asmlinkage int __exception do_debug_exception(unsigned long addr, > if (interrupts_enabled(regs)) > trace_hardirqs_off(); > > - if (user_mode(regs) && !is_ttbr0_addr(instruction_pointer(regs))) > + if (user_mode(regs) && !is_ttbr0_addr(pc)) > arm64_apply_bp_hardening(); > > - if (!inf->fn(addr, esr, regs)) { > + if (!inf->fn(addr_if_watchpoint, esr, regs)) { > rv = 1; > } else { > arm64_notify_die(inf->name, regs, > - inf->sig, inf->code, (void __user *)addr, esr); > + inf->sig, inf->code, (void __user *)pc, esr); > rv = 0; > } > > -- > 2.11.0 >
Hi,
[This is an automated email]
This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all
The bot has tested the following trees: v4.20.13, v4.19.26, v4.14.104, v4.9.161, v4.4.176, v3.18.136.
v4.20.13: Failed to apply! Possible dependencies:
356607f21e60 ("kasan, arm64: fix up fault handling logic")
v4.19.26: Failed to apply! Possible dependencies:
356607f21e60 ("kasan, arm64: fix up fault handling logic")
359048f91db4 ("arm64/mm: Define esr_to_debug_fault_info()")
6fa998e83ef9 ("signal/arm64: Push siginfo generation into arm64_notify_die")
dbfe3828a6f3 ("arm64/mm: Reorganize arguments for is_el1_permission_fault()")
v4.14.104: Failed to apply! Possible dependencies:
1fc5dce78ad1 ("arm64/sve: Low-level SVE architectural state manipulation functions")
2923f5ea7738 ("nds32: Exception handling")
2c9120f3a86a ("arm64: signal: Make force_signal_inject more robust")
356607f21e60 ("kasan, arm64: fix up fault handling logic")
359048f91db4 ("arm64/mm: Define esr_to_debug_fault_info()")
3eb0f5193b49 ("signal: Ensure every siginfo we send has all bits initialized")
3f7c86b2382e ("arm64: Update fault_info table with new exception types")
42dbf54e8890 ("arm64: consistently log ESR and page table")
526c3ddb6aa2 ("signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS")
532826f3712b ("arm64: Mirror arm for unimplemented compat syscalls")
6fa998e83ef9 ("signal/arm64: Push siginfo generation into arm64_notify_die")
92ff0674f5d8 ("arm64: mm: Rework unhandled user pagefaults to call arm64_force_sig_info")
94ef7ecbdf6f ("arm64: fpsimd: Correctly annotate exception helpers called from asm")
969e61ba87f9 ("arm64: make is_permission_fault() name clearer")
af40ff687bc9 ("arm64: signal: Ensure si_code is valid for all fault signals")
bc0ee4760364 ("arm64/sve: Core task context handling")
cc19846079a7 ("arm64: fault: Don't leak data in ESR context for user fault on kernel VA")
dbfe3828a6f3 ("arm64/mm: Reorganize arguments for is_el1_permission_fault()")
v4.9.161: Failed to apply! Possible dependencies:
0e3a9026396c ("arm64: mm: Update perf accounting to handle poison faults")
1f9b8936f36f ("arm64: Decode information from ESR upon mem faults")
32015c235603 ("arm64: exception: handle Synchronous External Abort")
356607f21e60 ("kasan, arm64: fix up fault handling logic")
359048f91db4 ("arm64/mm: Define esr_to_debug_fault_info()")
3eb0f5193b49 ("signal: Ensure every siginfo we send has all bits initialized")
532826f3712b ("arm64: Mirror arm for unimplemented compat syscalls")
67ce16ec15ce ("arm64: mm: print out correct page table entries")
6fa998e83ef9 ("signal/arm64: Push siginfo generation into arm64_notify_die")
786889636ad7 ("arm64: Handle faults caused by inadvertent user access with PAN enabled")
7edda0886bc3 ("acpi: apei: handle SEA notification type for ARMv8")
83016b204225 ("arm64: mm: print file name of faulting vma")
92ff0674f5d8 ("arm64: mm: Rework unhandled user pagefaults to call arm64_force_sig_info")
969e61ba87f9 ("arm64: make is_permission_fault() name clearer")
a8ada146f517 ("arm64: Update the synchronous external abort fault description")
b824b9306823 ("arm64: print a fault message when attempting to write RO memory")
c07ab957d9af ("arm64: Call __show_regs directly")
cc19846079a7 ("arm64: fault: Don't leak data in ESR context for user fault on kernel VA")
dbfe3828a6f3 ("arm64/mm: Reorganize arguments for is_el1_permission_fault()")
e7c600f149b8 ("arm64: hwpoison: add VM_FAULT_HWPOISON[_LARGE] handling")
v4.4.176: Failed to apply! Possible dependencies:
09a6adf53d42 ("arm64: mm: unaligned access by user-land should be received as SIGBUS")
0a8ea52c3eb1 ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature")
1f9b8936f36f ("arm64: Decode information from ESR upon mem faults")
2dd0e8d2d2a1 ("arm64: Kprobes with single stepping support")
32015c235603 ("arm64: exception: handle Synchronous External Abort")
356607f21e60 ("kasan, arm64: fix up fault handling logic")
359048f91db4 ("arm64/mm: Define esr_to_debug_fault_info()")
57f4959bad0a ("arm64: kernel: Add support for User Access Override")
6afedcd23cfd ("arm64: mm: Add trace_irqflags annotations to do_debug_exception()")
7dd01aef0557 ("arm64: trap userspace "dc cvau" cache operation on errata-affected core")
9dbd5bb25c56 ("arm64: Refactor sysinstr exception handling")
a8ada146f517 ("arm64: Update the synchronous external abort fault description")
bbb1681ee365 ("arm64: mm: mark fault_info table const")
d5370f754875 ("arm64: prefetch: add alternative pattern for CPUs without a prefetcher")
d59bee887231 ("arm64: Add more test functions to insn.c")
e04a28d45ff3 ("arm64: debug: re-enable irqs before sending breakpoint SIGTRAP")
e7227d0e528f ("arm64: Cleanup SCTLR flags")
v3.18.136: Failed to apply! Possible dependencies:
09a6adf53d42 ("arm64: mm: unaligned access by user-land should be received as SIGBUS")
2dd0e8d2d2a1 ("arm64: Kprobes with single stepping support")
31dde116cb08 ("arm64: Replace set_arch_dma_coherent_ops with arch_setup_dma_ops")
3505f30fb6a9 ("ARM64 / ACPI: If we chose to boot from acpi then disable FDT")
359048f91db4 ("arm64/mm: Define esr_to_debug_fault_info()")
37655163ce1a ("ARM64 / ACPI: Get RSDP and ACPI boot-time tables")
587064b610c7 ("arm64: Add framework for legacy instruction emulation")
6933de0ca0b7 ("ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64")
7c59a3df15df ("ARM64 / ACPI: Get PSCI flags in FADT for PSCI init")
86dca36e6ba0 ("arm64: use private ratelimit state along with show_unhandled_signals")
876945dbf649 ("arm64: Hook up IOMMU dma_ops")
9b79f52d1a70 ("arm64: Add support for hooks to handle undefined instructions")
b10d79f76085 ("ARM64 / ACPI: Introduce early_param "acpi=" to enable/disable ACPI")
b6197b93fa4b ("arm64 : Introduce support for ACPI _CCA object")
bbb1681ee365 ("arm64: mm: mark fault_info table const")
d8f4f161e31f ("ACPI: move arm64 GSI IRQ model to generic GSI IRQ layer")
de7ee503f279 ("arm64: introduce is_device_dma_coherent")
f871d2680707 ("arm64: Fix show_unhandled_signal_ratelimited usage")
fbe61ec71ac9 ("ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi")
fccb9a81fd08 ("ARM64 / ACPI: Parse MADT for SMP initialization")
How should we proceed with this patch?
--
Thanks,
Sasha
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index efb7b2cbead5..ef46925096f0 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -824,11 +824,12 @@ void __init hook_debug_fault_code(int nr, debug_fault_info[nr].name = name; } -asmlinkage int __exception do_debug_exception(unsigned long addr, +asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, struct pt_regs *regs) { const struct fault_info *inf = esr_to_debug_fault_info(esr); + unsigned long pc = instruction_pointer(regs); int rv; /* @@ -838,14 +839,14 @@ asmlinkage int __exception do_debug_exception(unsigned long addr, if (interrupts_enabled(regs)) trace_hardirqs_off(); - if (user_mode(regs) && !is_ttbr0_addr(instruction_pointer(regs))) + if (user_mode(regs) && !is_ttbr0_addr(pc)) arm64_apply_bp_hardening(); - if (!inf->fn(addr, esr, regs)) { + if (!inf->fn(addr_if_watchpoint, esr, regs)) { rv = 1; } else { arm64_notify_die(inf->name, regs, - inf->sig, inf->code, (void __user *)addr, esr); + inf->sig, inf->code, (void __user *)pc, esr); rv = 0; }
FAR_EL1 is UNKNOWN for all debug exceptions other than those caused by taking a hardware watchpoint. Unfortunately, if a debug handler returns a non-zero value, then we will propagate the UNKNOWN FAR value to userspace via the si_addr field of the SIGTRAP siginfo_t. Instead, let's set si_addr to take on the PC of the faulting instruction, which we have available in the current pt_regs. Cc: <stable@vger.kernel.org> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/mm/fault.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)