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| author | Catalin Marinas <catalin.marinas@arm.com> | 2021-12-14 18:11:52 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-12-14 18:11:52 +0000 |
| commit | 580b536b504fb13bea6e19e399e207e7253ca30a (patch) | |
| tree | 6f8f0d3bafd40c186bad31a9afb07f8789aa9c89 /Documentation | |
| parent | d58071a8a76d779eedab38033ae4c821c30295a5 (diff) | |
| parent | 35b6b28e69985eafb20b3b2c7bd6eca452b56b53 (diff) | |
| download | linux-580b536b504fb13bea6e19e399e207e7253ca30a.tar.bz2 | |
Merge 'arm64/for-next/fixes' into for-next/bti
Needed for the arch/arm64/kernel/entry-ftrace.S fix.
* commit 'arm64/for-next/fixes^^':
arm64: ftrace: add missing BTIs
arm64: kexec: use __pa_symbol(empty_zero_page)
arm64: update PAC description for kernel
Diffstat (limited to 'Documentation')
| -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, |