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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-12-02 07:57:27 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-23 21:31:14 +1100 |
| commit | 902137ba8e469ed07c7f120a390161937a6288fb (patch) | |
| tree | 031cb524d3cd71a32efe368600dbc1c2d93b9117 /arch/powerpc/kernel/vdso32/getcpu.S | |
| parent | 8c452a889821ca0cd2a5f2e3e87fbc01e56408cb (diff) | |
powerpc/32: Add VDSO version of getcpu on non SMP
Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added
getcpu() for PPC64 only, by making use of a user readable general
purpose SPR.
PPC32 doesn't have any such SPR.
For non SMP, just return CPU id 0 from the VDSO directly.
PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0.
Before the patch, vdsotest reported:
getcpu: syscall: 1572 nsec/call
getcpu: libc: 1787 nsec/call
getcpu: vdso: not tested
Now, vdsotest reports:
getcpu: syscall: 1582 nsec/call
getcpu: libc: 502 nsec/call
getcpu: vdso: 187 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr
Diffstat (limited to 'arch/powerpc/kernel/vdso32/getcpu.S')
| -rw-r--r-- | arch/powerpc/kernel/vdso32/getcpu.S | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso32/getcpu.S b/arch/powerpc/kernel/vdso32/getcpu.S index 63e914539e1a..90b39af14383 100644 --- a/arch/powerpc/kernel/vdso32/getcpu.S +++ b/arch/powerpc/kernel/vdso32/getcpu.S @@ -15,6 +15,7 @@ * int __kernel_getcpu(unsigned *cpu, unsigned *node); * */ +#if defined(CONFIG_PPC64) V_FUNCTION_BEGIN(__kernel_getcpu) .cfi_startproc mfspr r5,SPRN_SPRG_VDSO_READ @@ -31,3 +32,19 @@ V_FUNCTION_BEGIN(__kernel_getcpu) blr .cfi_endproc V_FUNCTION_END(__kernel_getcpu) +#elif !defined(CONFIG_SMP) +V_FUNCTION_BEGIN(__kernel_getcpu) + .cfi_startproc + cmpwi cr0, r3, 0 + cmpwi cr1, r4, 0 + li r5, 0 + beq cr0, 1f + stw r5, 0(r3) +1: li r3, 0 /* always success */ + crclr cr0*4+so + beqlr cr1 + stw r5, 0(r4) + blr + .cfi_endproc +V_FUNCTION_END(__kernel_getcpu) +#endif |