diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2022-11-25 12:42:14 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-02-06 17:48:54 +0300 |
| commit | 717cce3bdcf34705417f641bf2fcdf9b038ec36c (patch) | |
| tree | ce78b376b3e6ddc1e8b151ed5f46acd61750f213 /arch/x86/include/asm/segment.h | |
| parent | 4c382d723edce1b3c72b55b1b505cf5526a56afc (diff) | |
| download | linux-717cce3bdcf34705417f641bf2fcdf9b038ec36c.tar.xz | |
x86/cpu: Provide the full setup for getcpu() on x86-32
setup_getcpu() configures two things:
- it writes the current CPU & node information into MSR_TSC_AUX
- it writes the same information as a GDT entry.
By using the "full" setup_getcpu() on i386 it is possible to read the CPU
information in userland via RDTSCP() or via LSL from the GDT.
Provide an GDT_ENTRY_CPUNODE for x86-32 and make the setup function
unconditionally available.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Link: https://lore.kernel.org/r/20221125094216.3663444-2-bigeasy@linutronix.de
Diffstat (limited to 'arch/x86/include/asm/segment.h')
| -rw-r--r-- | arch/x86/include/asm/segment.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index c390a672d560..794f69625780 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -96,7 +96,7 @@ * * 26 - ESPFIX small SS * 27 - per-cpu [ offset to per-cpu data area ] - * 28 - unused + * 28 - VDSO getcpu * 29 - unused * 30 - unused * 31 - TSS for double fault handler @@ -119,6 +119,7 @@ #define GDT_ENTRY_ESPFIX_SS 26 #define GDT_ENTRY_PERCPU 27 +#define GDT_ENTRY_CPUNODE 28 #define GDT_ENTRY_DOUBLEFAULT_TSS 31 @@ -159,6 +160,8 @@ # define __KERNEL_PERCPU 0 #endif +#define __CPUNODE_SEG (GDT_ENTRY_CPUNODE*8 + 3) + #else /* 64-bit: */ #include <asm/cache.h> @@ -226,8 +229,6 @@ #define GDT_ENTRY_TLS_ENTRIES 3 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8) -#ifdef CONFIG_X86_64 - /* Bit size and mask of CPU number stored in the per CPU data (and TSC_AUX) */ #define VDSO_CPUNODE_BITS 12 #define VDSO_CPUNODE_MASK 0xfff @@ -265,7 +266,6 @@ static inline void vdso_read_cpunode(unsigned *cpu, unsigned *node) } #endif /* !__ASSEMBLY__ */ -#endif /* CONFIG_X86_64 */ #ifdef __KERNEL__ |