ARM: 6528/1: Use CTR for the I-cache line size on ARMv7

The current implementation of the v7_coherent_*_range function assumes
that the D and I cache lines have the same size, which is incorrect
architecturally. This patch adds the icache_line_size macro which reads
the CTR register. The main loop in v7_coherent_*_range is split in two
independent loops or the D and I caches. This also has the performance
advantage that the DSB is moved outside the main loop.

Reported-by: Kevin Sapp <ksapp@quicinc.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index a3ebf7a..6136e68 100644 (file)
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -173,15 +173,22 @@ ENTRY(v7_coherent_user_range)
  UNWIND(.fnstart               )
        dcache_line_size r2, r3
        sub     r3, r2, #1
-       bic     r0, r0, r3
+       bic     r12, r0, r3
 1:
- USER( mcr     p15, 0, r0, c7, c11, 1  )       @ clean D line to the point of unification
+ USER( mcr     p15, 0, r12, c7, c11, 1 )       @ clean D line to the point of unification
+       add     r12, r12, r2
+       cmp     r12, r1
+       blo     1b
        dsb
- USER( mcr     p15, 0, r0, c7, c5, 1   )       @ invalidate I line
-       add     r0, r0, r2
+       icache_line_size r2, r3
+       sub     r3, r2, #1
+       bic     r12, r0, r3
 2:
-       cmp     r0, r1
-       blo     1b
+ USER( mcr     p15, 0, r12, c7, c5, 1  )       @ invalidate I line
+       add     r12, r12, r2
+       cmp     r12, r1
+       blo     2b
+3:
        mov     r0, #0
        ALT_SMP(mcr     p15, 0, r0, c7, c1, 6)  @ invalidate BTB Inner Shareable
        ALT_UP(mcr      p15, 0, r0, c7, c5, 6)  @ invalidate BTB
@@ -194,10 +201,10 @@ ENTRY(v7_coherent_user_range)
  * isn't mapped, just try the next page.
  */
 9001:
-       mov     r0, r0, lsr #12
-       mov     r0, r0, lsl #12
-       add     r0, r0, #4096
-       b       2b
+       mov     r12, r12, lsr #12
+       mov     r12, r12, lsl #12
+       add     r12, r12, #4096
+       b       3b
  UNWIND(.fnend         )
 ENDPROC(v7_coherent_kern_range)
 ENDPROC(v7_coherent_user_range)

diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index 321555b..b795afd 100644 (file)
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -72,6 +72,16 @@
        mov     \reg, \reg, lsl \tmp            @ actual cache line size
        .endm
 
+/*
+ * icache_line_size - get the minimum I-cache line size from the CTR register
+ * on ARMv7.
+ */
+       .macro  icache_line_size, reg, tmp
+       mrc     p15, 0, \tmp, c0, c0, 1         @ read ctr
+       and     \tmp, \tmp, #0xf                @ cache line size encoding
+       mov     \reg, #4                        @ bytes per word
+       mov     \reg, \reg, lsl \tmp            @ actual cache line size
+       .endm
 
 /*
  * Sanity check the PTE configuration for the code below - which makes