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authorMark Brown <broonie@kernel.org>2022-08-29 17:49:19 +0200
committerCatalin Marinas <catalin.marinas@arm.com>2022-09-21 18:26:58 +0200
commitf285da05c62a429f1978c5520cf069d483a7d9af (patch)
treeea5ea993037c19f58324b882938cfe4bad875857
parentkselftest/arm64: Add test coverage for NT_ARM_TLS (diff)
downloadlinux-f285da05c62a429f1978c5520cf069d483a7d9af.tar.xz
linux-f285da05c62a429f1978c5520cf069d483a7d9af.zip
arm64/ptrace: Document extension of NT_ARM_TLS to cover TPIDR2_EL0
In order to allow debuggers to discover lazily saved SME state we need to provide access to TPIDR2_EL0, we will extend the existing NT_ARM_TLS used for TPIDR to also include TPIDR2_EL0 as the second register in the regset. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220829154921.837871-3-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--Documentation/arm64/sme.rst3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/arm64/sme.rst b/Documentation/arm64/sme.rst
index 937147f58cc5..16d2db4c2e2e 100644
--- a/Documentation/arm64/sme.rst
+++ b/Documentation/arm64/sme.rst
@@ -331,6 +331,9 @@ The regset data starts with struct user_za_header, containing:
been read if a PTRACE_GETREGSET of NT_ARM_ZA were executed for each thread
when the coredump was generated.
+* The NT_ARM_TLS note will be extended to two registers, the second register
+ will contain TPIDR2_EL0 on systems that support SME and will be read as
+ zero with writes ignored otherwise.
9. System runtime configuration
--------------------------------