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| author | Michael Ellerman <mpe@ellerman.id.au> | 2020-11-26 14:10:01 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-03 15:01:10 +0100 |
| commit | 5c189c523e78d4a70e874477e4b0628fd74207e4 (patch) | |
| tree | 2df65630c6d9700000f8ef01f648ce4e3fc8057b /arch/powerpc/include/asm/vdso | |
| parent | powerpc/time: Move timebase functions into new asm/vdso/timebase.h (diff) | |
| download | linux-5c189c523e78d4a70e874477e4b0628fd74207e4.tar.xz linux-5c189c523e78d4a70e874477e4b0628fd74207e4.zip | |
powerpc/time: Fix mftb()/get_tb() for use with the compat VDSO
When we're building the compat VDSO we are building 32-bit code but in
the context of a 64-bit kernel configuration.
To make this work we need to be careful in some places when using
ifdefs to differentiate between CONFIG_PPC64 and __powerpc64__.
CONFIG_PPC64 indicates the kernel we're building is 64-bit, but it
doesn't tell us that we're currently building 64-bit code - we could
be building 32-bit code for the compat VDSO.
On the other hand __powerpc64__ tells us that we are currently
building 64-bit code (and therefore we must also be building a 64-bit
kernel).
In the case of get_tb() we want to use the 32-bit code sequence
regardless of whether the kernel we're building for is 64-bit or
32-bit, what matters is the word size of the current object. So we
need to check __powerpc64__ to decide if we use mftb() or the
mftbu()/mftb() sequence.
For mftb() the logic for CPU_FTR_CELL_TB_BUG only makes sense if we're
building 64-bit code, so guard that with a __powerpc64__ check.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-4-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc/include/asm/vdso')
| -rw-r--r-- | arch/powerpc/include/asm/vdso/timebase.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/vdso/timebase.h b/arch/powerpc/include/asm/vdso/timebase.h index ac6769b348c6..b558b07959ce 100644 --- a/arch/powerpc/include/asm/vdso/timebase.h +++ b/arch/powerpc/include/asm/vdso/timebase.h @@ -8,7 +8,11 @@ #include <asm/reg.h> -#if defined(CONFIG_PPC_CELL) || defined(CONFIG_E500) +/* + * We use __powerpc64__ here because we want the compat VDSO to use the 32-bit + * version below in the else case of the ifdef. + */ +#if defined(__powerpc64__) && (defined(CONFIG_PPC_CELL) || defined(CONFIG_E500)) #define mftb() ({unsigned long rval; \ asm volatile( \ "90: mfspr %0, %2;\n" \ @@ -49,7 +53,11 @@ static inline u64 get_tb(void) { unsigned int tbhi, tblo, tbhi2; - if (IS_ENABLED(CONFIG_PPC64)) + /* + * We use __powerpc64__ here not CONFIG_PPC64 because we want the compat + * VDSO to use the 32-bit compatible version in the while loop below. + */ + if (__is_defined(__powerpc64__)) return mftb(); do { |