diff options
| author | James Morse <james.morse@arm.com> | 2015-07-22 19:05:54 +0100 |
|---|---|---|
| committer | David Brown <david.brown@linaro.org> | 2015-12-03 16:53:53 -0800 |
| commit | 20af540051e1c1f7a7d9b9e4613c1ecc53ded4a6 (patch) | |
| tree | 0c02d4d7b3de8239ac87cb0d01cfe51cc0263b4b /arch/arm64/include/asm/futex.h | |
| parent | e7aa2ecf27faab420d6dd3b173419f6fd7bf85be (diff) | |
arm64: kernel: Add support for Privileged Access Neverv3.18/topic/PAN
commit 338d4f49d6f7114a017d294ccf7374df4f998edc upstream.
'Privileged Access Never' is a new arm8.1 feature which prevents
privileged code from accessing any virtual address where read or write
access is also permitted at EL0.
This patch enables the PAN feature on all CPUs, and modifies {get,put}_user
helpers temporarily to permit access.
This will catch kernel bugs where user memory is accessed directly.
'Unprivileged loads and stores' using ldtrb et al are unaffected by PAN.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
[will: use ALTERNATIVE in asm and tidy up pan_enable check]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: David Brown <david.brown@linaro.org>
Diffstat (limited to 'arch/arm64/include/asm/futex.h')
| -rw-r--r-- | arch/arm64/include/asm/futex.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 5f750dc96e0f..667346273d9b 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -20,10 +20,16 @@ #include <linux/futex.h> #include <linux/uaccess.h> + +#include <asm/alternative.h> +#include <asm/cpufeature.h> #include <asm/errno.h> +#include <asm/sysreg.h> #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ asm volatile( \ + ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ "1: ldxr %w1, %2\n" \ insn "\n" \ "2: stlxr %w3, %w0, %2\n" \ @@ -39,6 +45,8 @@ " .align 3\n" \ " .quad 1b, 4b, 2b, 4b\n" \ " .popsection\n" \ + ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ + CONFIG_ARM64_PAN) \ : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \ : "r" (oparg), "Ir" (-EFAULT) \ : "memory") |