From: Romain Naour <romain.naour@xxxxxxxxx>
commit 1d7ba0165d8206ac073f7ac3b14fc0836b66eae7 upstream
>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] '24640f233b46 ("mips: Add support for generic vDSO")'
Signed-off-by: Romain Naour <romain.naour@xxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/vdso/gettimeofday.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/arch/mips/vdso/gettimeofday.c
+++ b/arch/mips/vdso/gettimeofday.c
@@ -18,6 +18,12 @@
#include <asm/unistd.h>
#include <asm/vdso.h>
+#if MIPS_ISA_REV < 6
+#define VDSO_SYSCALL_CLOBBERS "hi", "lo",
+#else
+#define VDSO_SYSCALL_CLOBBERS
+#endif
+
#ifdef CONFIG_MIPS_CLOCK_VSYSCALL
static __always_inline long gettimeofday_fallback(struct timeval *_tv,
@@ -34,7 +40,9 @@ static __always_inline long gettimeofday
: "=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");
+ "$14", "$15", "$24", "$25",
+ VDSO_SYSCALL_CLOBBERS
+ "memory");
return error ? -ret : ret;
}
@@ -55,7 +63,9 @@ static __always_inline long clock_gettim
: "=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");
+ "$14", "$15", "$24", "$25",
+ VDSO_SYSCALL_CLOBBERS
+ "memory");
return error ? -ret : ret;
}
