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| author | Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> | 2021-12-01 06:40:10 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-12-02 13:13:35 +0300 |
| commit | ce39d473d1edd6914e1eed097deb0c0612baa8f6 (patch) | |
| tree | 7769dfb833bd3b1e2e94f45991bb749bf0104104 | |
| parent | 94902d849e85093aafcdbea2be8e2beff47233e6 (diff) | |
| download | linux-ce39d473d1edd6914e1eed097deb0c0612baa8f6.tar.xz | |
arm64: update PAC description for kernel
Remove the paragraph which has nothing to do with the kernel and
add PAC description related to kernel.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Link: https://lore.kernel.org/r/20211201034014.20048-1-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | Documentation/arm64/pointer-authentication.rst | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/Documentation/arm64/pointer-authentication.rst b/Documentation/arm64/pointer-authentication.rst index f127666ea3a8..e5dad2e40aa8 100644 --- a/Documentation/arm64/pointer-authentication.rst +++ b/Documentation/arm64/pointer-authentication.rst @@ -53,11 +53,10 @@ The number of bits that the PAC occupies in a pointer is 55 minus the virtual address size configured by the kernel. For example, with a virtual address size of 48, the PAC is 7 bits wide. -Recent versions of GCC can compile code with APIAKey-based return -address protection when passed the -msign-return-address option. This -uses instructions in the HINT space (unless -march=armv8.3-a or higher -is also passed), and such code can run on systems without the pointer -authentication extension. +When ARM64_PTR_AUTH_KERNEL is selected, the kernel will be compiled +with HINT space pointer authentication instructions protecting +function returns. Kernels built with this option will work on hardware +with or without pointer authentication support. In addition to exec(), keys can also be reinitialized to random values using the PR_PAC_RESET_KEYS prctl. A bitmask of PR_PAC_APIAKEY, |