diff options
| author | Xin Li <xin3.li@intel.com> | 2023-03-21 23:17:58 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-08-08 09:31:43 +0200 |
| commit | 39163d5479285a36522b6e8f9cc568cc4987db08 (patch) | |
| tree | 60381ff5e9234da868a1b48de46862b54b9b85ca | |
| parent | bee6cf1a80b54548a039e224c651bb15b644a480 (diff) | |
| download | linux-39163d5479285a36522b6e8f9cc568cc4987db08.tar.gz | |
x86/vdso: Choose the right GDT_ENTRY_CPUNODE for 32-bit getcpu() on 64-bit kernel
The vDSO getcpu() reads CPU ID from the GDT_ENTRY_CPUNODE entry when the RDPID
instruction is not available. And GDT_ENTRY_CPUNODE is defined as 28 on 32-bit
Linux kernel and 15 on 64-bit. But the 32-bit getcpu() on 64-bit Linux kernel
is compiled with 32-bit Linux kernel GDT_ENTRY_CPUNODE, i.e., 28, beyond the
64-bit Linux kernel GDT limit. Thus, it just fails _silently_.
When BUILD_VDSO32_64 is defined, choose the 64-bit Linux kernel GDT definitions
to compile the 32-bit getcpu().
Fixes: 877cff5296faa6e ("x86/vdso: Fake 32bit VDSO build on 64bit compile for vgetcpu")
Reported-by: kernel test robot <yujie.liu@intel.com>
Reported-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230322061758.10639-1-xin3.li@intel.com
Link: https://lore.kernel.org/oe-lkp/202303020903.b01fd1de-yujie.liu@intel.com
| -rw-r--r-- | arch/x86/include/asm/segment.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index 794f696257801..9d6411c659205 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -56,7 +56,7 @@ #define GDT_ENTRY_INVALID_SEG 0 -#ifdef CONFIG_X86_32 +#if defined(CONFIG_X86_32) && !defined(BUILD_VDSO32_64) /* * The layout of the per-CPU GDT under Linux: * |