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| author | Benjamin Gray <bgray@linux.ibm.com> | 2023-06-19 10:36:26 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-06-19 10:36:26 +0300 |
| commit | 884ad5c52da253e5d38f947cd8d1d9412a47429c (patch) | |
| tree | 48ecae3a0bdfe4a4ae24769b9231c118263db676 /include/uapi | |
| parent | be98fcf7c10dea74e9c3e2cd0018e47bdee67442 (diff) | |
| download | linux-884ad5c52da253e5d38f947cd8d1d9412a47429c.tar.xz | |
powerpc/ptrace: Expose DEXCR and HDEXCR registers to ptrace
The DEXCR register is of interest when ptracing processes. Currently it
is static, but eventually will be dynamically controllable by a process.
If a process can control its own, then it is useful for it to be
ptrace-able to (e.g., for checkpoint-restore functionality).
It is also relevant to core dumps (the NPHIE aspect in particular),
which use the ptrace mechanism (or is it the other way around?) to
decide what to dump. The HDEXCR is useful here too, as the NPHIE aspect
may be set in the HDEXCR without being set in the DEXCR. Although the
HDEXCR is per-cpu and we don't track it in the task struct (it's useless
in normal operation), it would be difficult to imagine why a hypervisor
would set it to different values within a guest. A hypervisor cannot
safely set NPHIE differently at least, as that would break programs.
Expose a read-only view of the userspace DEXCR and HDEXCR to ptrace.
The HDEXCR is always readonly, and is useful for diagnosing the core
dumps (as the HDEXCR may set NPHIE without the DEXCR setting it).
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
[mpe: Use lower_32_bits() rather than open coding]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616034846.311705-7-bgray@linux.ibm.com
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/elf.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index ac3da855fb19..cfa31f1eb5d7 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -403,6 +403,7 @@ typedef struct elf64_shdr { #define NT_PPC_TM_CPPR 0x10e /* TM checkpointed Program Priority Register */ #define NT_PPC_TM_CDSCR 0x10f /* TM checkpointed Data Stream Control Register */ #define NT_PPC_PKEY 0x110 /* Memory Protection Keys registers */ +#define NT_PPC_DEXCR 0x111 /* PowerPC DEXCR registers */ #define NT_386_TLS 0x200 /* i386 TLS slots (struct user_desc) */ #define NT_386_IOPERM 0x201 /* x86 io permission bitmap (1=deny) */ #define NT_X86_XSTATE 0x202 /* x86 extended state using xsave */ |