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x86/vdso: Fix output operand size of RDPID

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[ Upstream commit ac9c408ed19d535289ca59200dd6a44a6a2d6036 ]

RDPID instruction outputs to a word-sized register (64-bit on x86_64 and
32-bit on x86_32). Use an unsigned long variable to store the correct size.

LSL outputs to 32-bit register, use %k operand prefix to always print the
32-bit name of the register.

Use RDPID insn mnemonic while at it as the minimum binutils version of
2.30 supports it.

  [ bp: Merge two patches touching the same function into a single one. ]

Fixes: ffebbaedc8 ("x86/vdso: Introduce helper functions for CPU and node number")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250616095315.230620-1-ubizjak@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Uros Bizjak 2025-06-16 11:52:57 +02:00 committed by Greg Kroah-Hartman
parent 1652f14cf3
commit d607e6b349
1 changed files with 4 additions and 4 deletions
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8
arch/x86/include/asm/segment.h
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@ -244,7 +244,7 @@ static inline unsigned long vdso_encode_cpunode(int cpu, unsigned long node)
static inline void vdso_read_cpunode(unsigned *cpu, unsigned *node)
{
unsigned int p;
unsigned long p;
/*
* Load CPU and node number from the GDT. LSL is faster than RDTSCP
@ -254,10 +254,10 @@ static inline void vdso_read_cpunode(unsigned *cpu, unsigned *node)
*
* If RDPID is available, use it.
*/
alternative_io ("lsl %[seg],%[p]",
".byte 0xf3,0x0f,0xc7,0xf8", /* RDPID %eax/rax */
alternative_io ("lsl %[seg],%k[p]",
"rdpid %[p]",
X86_FEATURE_RDPID,
[p] "=a" (p), [seg] "r" (__CPUNODE_SEG));
[p] "=r" (p), [seg] "r" (__CPUNODE_SEG));
if (cpu)
*cpu = (p & VDSO_CPUNODE_MASK);