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| author | Dave Martin <Dave.Martin@arm.com> | 2020-03-16 16:50:45 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-03-16 17:19:48 +0000 |
| commit | 8ef8f360cf30be12382f89ff48a57fbbd9b31c14 (patch) | |
| tree | 6060caf0bfe50a4c370c86625b7325f6199b746a /arch/arm64/include/uapi/asm/ptrace.h | |
| parent | 00e19ceec80b03a43f626f891fcc53e57919f1b3 (diff) | |
| download | linux-8ef8f360cf30be12382f89ff48a57fbbd9b31c14.tar.bz2 | |
arm64: Basic Branch Target Identification support
This patch adds the bare minimum required to expose the ARMv8.5
Branch Target Identification feature to userspace.
By itself, this does _not_ automatically enable BTI for any initial
executable pages mapped by execve(). This will come later, but for
now it should be possible to enable BTI manually on those pages by
using mprotect() from within the target process.
Other arches already using the generic mman.h are already using
0x10 for arch-specific prot flags, so we use that for PROT_BTI
here.
For consistency, signal handler entry points in BTI guarded pages
are required to be annotated as such, just like any other function.
This blocks a relatively minor attack vector, but comforming
userspace will have the annotations anyway, so we may as well
enforce them.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/uapi/asm/ptrace.h')
| -rw-r--r-- | arch/arm64/include/uapi/asm/ptrace.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index d1bb5b69f1ce..42cbe34d95ce 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -46,6 +46,7 @@ #define PSR_I_BIT 0x00000080 #define PSR_A_BIT 0x00000100 #define PSR_D_BIT 0x00000200 +#define PSR_BTYPE_MASK 0x00000c00 #define PSR_SSBS_BIT 0x00001000 #define PSR_PAN_BIT 0x00400000 #define PSR_UAO_BIT 0x00800000 @@ -55,6 +56,8 @@ #define PSR_Z_BIT 0x40000000 #define PSR_N_BIT 0x80000000 +#define PSR_BTYPE_SHIFT 10 + /* * Groups of PSR bits */ @@ -63,6 +66,12 @@ #define PSR_x 0x0000ff00 /* Extension */ #define PSR_c 0x000000ff /* Control */ +/* Convenience names for the values of PSTATE.BTYPE */ +#define PSR_BTYPE_NONE (0b00 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_JC (0b01 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_C (0b10 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_J (0b11 << PSR_BTYPE_SHIFT) + /* syscall emulation path in ptrace */ #define PTRACE_SYSEMU 31 #define PTRACE_SYSEMU_SINGLESTEP 32 |