| Message ID | 20210312004919.669614-15-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add support for Clang CFI | expand |
On Thu, Mar 11, 2021 at 04:49:16PM -0800, Sami Tolvanen wrote: > Disable CFI checking for functions that switch to linear mapping and > make an indirect call to a physical address, since the compiler only > understands virtual addresses and the CFI check for such indirect calls > would always fail. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> (I wonder if there is some value in a separate macro for "makes a PA call"? Might other things care about that besides just CFI?) Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 519d535532be..27f3797baa2e 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -136,7 +136,7 @@ static inline void cpu_install_idmap(void) * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD, * avoiding the possibility of conflicting TLB entries being allocated. */ -static inline void cpu_replace_ttbr1(pgd_t *pgdp) +static inline void __nocfi cpu_replace_ttbr1(pgd_t *pgdp) { typedef void (ttbr_replace_func)(phys_addr_t); extern ttbr_replace_func idmap_cpu_replace_ttbr1; diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h index dfba8cf921e5..a05bda363272 100644 --- a/arch/arm64/kernel/cpu-reset.h +++ b/arch/arm64/kernel/cpu-reset.h @@ -13,10 +13,10 @@ void __cpu_soft_restart(unsigned long el2_switch, unsigned long entry, unsigned long arg0, unsigned long arg1, unsigned long arg2); -static inline void __noreturn cpu_soft_restart(unsigned long entry, - unsigned long arg0, - unsigned long arg1, - unsigned long arg2) +static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry, + unsigned long arg0, + unsigned long arg1, + unsigned long arg2) { typeof(__cpu_soft_restart) *restart; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 7ec1c2ccdc0b..473212ff4d70 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1443,7 +1443,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, } #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 -static void +static void __nocfi kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused) { typedef void (kpti_remap_fn)(int, int, phys_addr_t);
Disable CFI checking for functions that switch to linear mapping and make an indirect call to a physical address, since the compiler only understands virtual addresses and the CFI check for such indirect calls would always fail. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/arm64/include/asm/mmu_context.h | 2 +- arch/arm64/kernel/cpu-reset.h | 8 ++++---- arch/arm64/kernel/cpufeature.c | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-)