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| author | Andre Przywara <andre.przywara@arm.com> | 2021-12-22 18:16:05 +0000 |
|---|---|---|
| committer | Mark Rutland <mark.rutland@arm.com> | 2022-01-07 14:10:13 +0000 |
| commit | fa754a55b3363266a999ef41dddc7a74a37a34cd (patch) | |
| tree | 925b945bd61d0facdd477aa66cafd62ad969794e | |
| parent | 1d2f934679b60b2f4095c3f132d3b0e7ef9d9717 (diff) | |
| download | boot-wrapper-aarch64-fa754a55b3363266a999ef41dddc7a74a37a34cd.tar.gz | |
pointer auth: Document CPU feature bit mask
When checking for the pointer authentication feature, we actually look
for *four* different CPUID feature sets.
Add a comment to make it more obvious that the 0xff is not a typo.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
| -rw-r--r-- | arch/aarch64/boot.S | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S index bfbb6ec..27ba449 100644 --- a/arch/aarch64/boot.S +++ b/arch/aarch64/boot.S @@ -38,7 +38,8 @@ ASM_FUNC(_start) /* Enable pointer authentication if present */ mrs x1, id_aa64isar1_el1 - ldr x2, =(((0xff) << 24) | (0xff << 4)) + /* We check for APA+API and GPA+GPI */ + ldr x2, =((0xff << 24) | (0xff << 4)) and x1, x1, x2 cbz x1, 1f |