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| author | Will Deacon <will@kernel.org> | 2020-05-28 18:00:51 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-28 18:00:51 +0100 |
| commit | d27865279f12035c730818aa1a0280fada866a37 (patch) | |
| tree | 5c4462885c2a6d7453b34ceb51d39b390030a2a6 /arch/arm64/kernel/signal.c | |
| parent | 342403bcb4dfe41324a0f6f4cb5a8d324f31c725 (diff) | |
| parent | a4eb355a3fdad85d16e4b098e8d56bb28b812ce0 (diff) | |
| download | linux-d27865279f12035c730818aa1a0280fada866a37.tar.gz linux-d27865279f12035c730818aa1a0280fada866a37.tar.bz2 linux-d27865279f12035c730818aa1a0280fada866a37.zip | |
Merge branch 'for-next/bti' into for-next/core
Support for Branch Target Identification (BTI) in user and kernel
(Mark Brown and others)
* for-next/bti: (39 commits)
arm64: vdso: Fix CFI directives in sigreturn trampoline
arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
arm64: bti: Fix support for userspace only BTI
arm64: kconfig: Update and comment GCC version check for kernel BTI
arm64: vdso: Map the vDSO text with guarded pages when built for BTI
arm64: vdso: Force the vDSO to be linked as BTI when built for BTI
arm64: vdso: Annotate for BTI
arm64: asm: Provide a mechanism for generating ELF note for BTI
arm64: bti: Provide Kconfig for kernel mode BTI
arm64: mm: Mark executable text as guarded pages
arm64: bpf: Annotate JITed code for BTI
arm64: Set GP bit in kernel page tables to enable BTI for the kernel
arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
arm64: bti: Support building kernel C code using BTI
arm64: Document why we enable PAC support for leaf functions
arm64: insn: Report PAC and BTI instructions as skippable
arm64: insn: Don't assume unrecognized HINTs are skippable
arm64: insn: Provide a better name for aarch64_insn_is_nop()
arm64: insn: Add constants for new HINT instruction decode
arm64: Disable old style assembly annotations
...
Diffstat (limited to 'arch/arm64/kernel/signal.c')
| -rw-r--r-- | arch/arm64/kernel/signal.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 339882db5a91..801d56cdf701 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -732,6 +732,22 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, regs->regs[29] = (unsigned long)&user->next_frame->fp; regs->pc = (unsigned long)ka->sa.sa_handler; + /* + * Signal delivery is a (wacky) indirect function call in + * userspace, so simulate the same setting of BTYPE as a BLR + * <register containing the signal handler entry point>. + * Signal delivery to a location in a PROT_BTI guarded page + * that is not a function entry point will now trigger a + * SIGILL in userspace. + * + * If the signal handler entry point is not in a PROT_BTI + * guarded page, this is harmless. + */ + if (system_supports_bti()) { + regs->pstate &= ~PSR_BTYPE_MASK; + regs->pstate |= PSR_BTYPE_C; + } + if (ka->sa.sa_flags & SA_RESTORER) sigtramp = ka->sa.sa_restorer; else |