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authorRick Edgecombe <rick.p.edgecombe@intel.com>2023-06-13 03:11:08 +0300
committerDave Hansen <dave.hansen@linux.intel.com>2023-08-03 01:01:51 +0300
commit67840ad0fa14ad49a605074b12d5b0f3c3113ed1 (patch)
tree7b134d61d3cadc36289a00923e71df1a23dd4ba2 /Documentation/arch
parent680ed2f15e70d079c8148589a3ce9426fc0ff914 (diff)
downloadlinux-67840ad0fa14ad49a605074b12d5b0f3c3113ed1.tar.xz
x86/shstk: Add ARCH_SHSTK_STATUS
CRIU and GDB need to get the current shadow stack and WRSS enablement status. This information is already available via /proc/pid/status, but this is inconvenient for CRIU because it involves parsing the text output in an area of the code where this is difficult. Provide a status arch_prctl(), ARCH_SHSTK_STATUS for retrieving the status. Have arg2 be a userspace address, and make the new arch_prctl simply copy the features out to userspace. Suggested-by: Mike Rapoport <rppt@kernel.org> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Tested-by: Pengfei Xu <pengfei.xu@intel.com> Tested-by: John Allen <john.allen@amd.com> Tested-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/all/20230613001108.3040476-43-rick.p.edgecombe%40intel.com
Diffstat (limited to 'Documentation/arch')
-rw-r--r--Documentation/arch/x86/shstk.rst6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/arch/x86/shstk.rst b/Documentation/arch/x86/shstk.rst
index f3553cc8c758..60260e809baf 100644
--- a/Documentation/arch/x86/shstk.rst
+++ b/Documentation/arch/x86/shstk.rst
@@ -79,6 +79,11 @@ arch_prctl(ARCH_SHSTK_UNLOCK, unsigned long features)
Unlock features. 'features' is a mask of all features to unlock. All
bits set are processed, unset bits are ignored. Only works via ptrace.
+arch_prctl(ARCH_SHSTK_STATUS, unsigned long addr)
+ Copy the currently enabled features to the address passed in addr. The
+ features are described using the bits passed into the others in
+ 'features'.
+
The return values are as follows. On success, return 0. On error, errno can
be::
@@ -86,6 +91,7 @@ be::
-ENOTSUPP if the feature is not supported by the hardware or
kernel.
-EINVAL arguments (non existing feature, etc)
+ -EFAULT if could not copy information back to userspace
The feature's bits supported are::