Re: [PATCH 1/6] powerpc/time: Rename mftbl() to mftb()
On Thu, 1 Oct 2020 12:42:39 + (UTC), Christophe Leroy wrote: > On PPC64, we have mftb(). > On PPC32, we have mftbl() and an #define mftb() mftbl(). > > mftb() and mftbl() are equivalent, their purpose is to read the > content of SPRN_TRBL, as returned by 'mftb' simplified instruction. > > binutils seems to define 'mftbl' instruction as an equivalent > of 'mftb'. > > [...] Applied to powerpc/next. [1/6] powerpc/time: Rename mftbl() to mftb() https://git.kernel.org/powerpc/c/15c102153e722cc6e0729764a7068c209a7469cd [2/6] powerpc/time: Make mftb() common to PPC32 and PPC64 https://git.kernel.org/powerpc/c/ff125fbcd45d1706861579dbe66e31f5b3f1e779 [3/6] powerpc/time: Avoid using get_tbl() and get_tbu() internally https://git.kernel.org/powerpc/c/942e89115b588b4b5df86930b5302a5c07b820ba [4/6] powerpc/time: Remove get_tbu() https://git.kernel.org/powerpc/c/e8d5bf30eafc37e31ce68bc7ccf1db970fe3cd04 [5/6] powerpc/time: Make get_tbl() common to PPC32 and PPC64 https://git.kernel.org/powerpc/c/1156a6285cd38e5a6987ddee3758e7954c56cb3d [6/6] powerpc/time: Make get_tb() common to PPC32 and PPC64 https://git.kernel.org/powerpc/c/9686e431c683ee7b8aca0f3985c244aee3d9f30d cheers
Re: [PATCH 1/6] powerpc/time: Rename mftbl() to mftb()
On Thu, Oct 01, 2020 at 12:42:39PM +, Christophe Leroy wrote: > On PPC64, we have mftb(). > On PPC32, we have mftbl() and an #define mftb() mftbl(). > > mftb() and mftbl() are equivalent, their purpose is to read the > content of SPRN_TRBL, as returned by 'mftb' simplified instruction. > > binutils seems to define 'mftbl' instruction as an equivalent > of 'mftb'. > > However in both 32 bits and 64 bits documentation, only 'mftb' is > defined, and when performing a disassembly with objdump, the displayed > instruction is 'mftb' > > No need to have two ways to do the same thing with different > names, rename mftbl() to have only mftb(). There are mttbl and mttbu insns (and no mttb insn); they write a 32-bit half for the time base. There is an mftb, and an mftbu. mftbu reads the upper half, while mftb reads the *whole* register. SPR 269 is the TBU register, while SPR 268 is called both TB and TBL. Yes, it is confusing :-) The "mftb" name is much clearer than "mftbl" (on 64-bit), because it reads the whole 64-bit register. On 32-bit mftbl is clearer (but not defined in the architecture, not officially an insn or even an extended mnemonic). Segher
[PATCH 1/6] powerpc/time: Rename mftbl() to mftb()
On PPC64, we have mftb().
On PPC32, we have mftbl() and an #define mftb() mftbl().
mftb() and mftbl() are equivalent, their purpose is to read the
content of SPRN_TRBL, as returned by 'mftb' simplified instruction.
binutils seems to define 'mftbl' instruction as an equivalent
of 'mftb'.
However in both 32 bits and 64 bits documentation, only 'mftb' is
defined, and when performing a disassembly with objdump, the displayed
instruction is 'mftb'
No need to have two ways to do the same thing with different
names, rename mftbl() to have only mftb().
Signed-off-by: Christophe Leroy
---
arch/powerpc/include/asm/reg.h | 5 ++---
arch/powerpc/include/asm/time.h | 2 +-
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 788058af1d44..c66dcdb47c44 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1439,19 +1439,18 @@ static inline void msr_check_and_clear(unsigned long
bits)
#else /* __powerpc64__ */
#if defined(CONFIG_PPC_8xx)
-#define mftbl()({unsigned long rval; \
+#define mftb() ({unsigned long rval; \
asm volatile("mftbl %0" : "=r" (rval)); rval;})
#define mftbu()({unsigned long rval; \
asm volatile("mftbu %0" : "=r" (rval)); rval;})
#else
-#define mftbl()({unsigned long rval; \
+#define mftb() ({unsigned long rval; \
asm volatile("mfspr %0, %1" : "=r" (rval) : \
"i" (SPRN_TBRL)); rval;})
#define mftbu()({unsigned long rval; \
asm volatile("mfspr %0, %1" : "=r" (rval) : \
"i" (SPRN_TBRU)); rval;})
#endif
-#define mftb() mftbl()
#endif /* !__powerpc64__ */
#define mttbl(v) asm volatile("mttbl %0":: "r"(v))
diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
index a80abf64c8a5..b0fb8456305f 100644
--- a/arch/powerpc/include/asm/time.h
+++ b/arch/powerpc/include/asm/time.h
@@ -50,7 +50,7 @@ struct div_result {
static inline unsigned long get_tbl(void)
{
- return mftbl();
+ return mftb();
}
static inline unsigned int get_tbu(void)
--
2.25.0
