[PATCH] mips: Do not include hi and lo in clobber list for R6
From: Romain Naour <hidden>
Date: 2020-07-25 13:25:40
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
From [1]
"GCC 10 (PR 91233) won't silently allow registers that are not architecturally
available to be present in the clobber list anymore, resulting in build failure
for mips*r6 targets in form of:
...
.../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target
146 | __asm__ volatile ( \
| ^~~~~~~
This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension.
This patch provides the alternative clobber list for r6 targets that won't include
those registers."
Since kernel 5.4 and mips support for generic vDSO [2], the kernel fail to build
for mips r6 cpus with gcc 10 for the same reason as glibc.
[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8
[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24640f233b466051ad3a5d2786d2951e43026c9d
Signed-off-by: Romain Naour <redacted>
---
arch/mips/include/asm/vdso/gettimeofday.h | 45 +++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/arch/mips/include/asm/vdso/gettimeofday.h b/arch/mips/include/asm/vdso/gettimeofday.h
index c63ddcaea54c..6192d94928b9 100644
--- a/arch/mips/include/asm/vdso/gettimeofday.h
+++ b/arch/mips/include/asm/vdso/gettimeofday.h@@ -30,12 +30,21 @@ static __always_inline long gettimeofday_fallback( register long nr asm("v0") = __NR_gettimeofday; register long error asm("a3"); +#if __mips_isa_rev >= 6 + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (tv), "r" (tz), "r" (nr) + : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", + "$14", "$15", "$24", "$25", "memory"); +#else asm volatile( " syscall\n" : "=r" (ret), "=r" (error) : "r" (tv), "r" (tz), "r" (nr) : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25", "hi", "lo", "memory"); +#endif return error ? -ret : ret; }
@@ -54,12 +63,21 @@ static __always_inline long clock_gettime_fallback( #endif register long error asm("a3"); +#if __mips_isa_rev >= 6 + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (clkid), "r" (ts), "r" (nr) + : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", + "$14", "$15", "$24", "$25", "memory"); +#else asm volatile( " syscall\n" : "=r" (ret), "=r" (error) : "r" (clkid), "r" (ts), "r" (nr) : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25", "hi", "lo", "memory"); +#endif return error ? -ret : ret; }
@@ -78,12 +96,21 @@ static __always_inline int clock_getres_fallback( #endif register long error asm("a3"); +#if __mips_isa_rev >= 6 + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (clkid), "r" (ts), "r" (nr) + : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", + "$14", "$15", "$24", "$25", "memory"); +#else asm volatile( " syscall\n" : "=r" (ret), "=r" (error) : "r" (clkid), "r" (ts), "r" (nr) : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25", "hi", "lo", "memory"); +#endif return error ? -ret : ret; }
@@ -100,12 +127,21 @@ static __always_inline long clock_gettime32_fallback( register long nr asm("v0") = __NR_clock_gettime; register long error asm("a3"); +#if __mips_isa_rev >= 6 + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (clkid), "r" (ts), "r" (nr) + : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", + "$14", "$15", "$24", "$25", "memory"); +#else asm volatile( " syscall\n" : "=r" (ret), "=r" (error) : "r" (clkid), "r" (ts), "r" (nr) : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25", "hi", "lo", "memory"); +#endif return error ? -ret : ret; }
@@ -120,12 +156,21 @@ static __always_inline int clock_getres32_fallback( register long nr asm("v0") = __NR_clock_getres; register long error asm("a3"); +#if __mips_isa_rev >= 6 + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (clkid), "r" (ts), "r" (nr) + : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", + "$14", "$15", "$24", "$25", "memory"); +#else asm volatile( " syscall\n" : "=r" (ret), "=r" (error) : "r" (clkid), "r" (ts), "r" (nr) : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24", "$25", "hi", "lo", "memory"); +#endif return error ? -ret : ret; }
--
2.25.4