Re: [PATCH v4 4/5] ARM: smp: Store current pointer in TPIDRURO register if available

Hi Russell,

Thanks for taking a look.

However, the next patch drops the 'ldr ip, [r4, #TI_TASK]' I am adding
here, so I won't be able to use this as-is.

I could just split the ldr/set_current sequence into two, and change
the first one into a mov in the following patch, and move the
set_current to right before where sp is updated.

I.e., in this patch

@@ -762,6 +764,8 @@ ENTRY(__switch_to)
        add     r7, r7, #TSK_STACK_CANARY & ~IMM12_MASK
        .endif
        ldr     r7, [r7, #TSK_STACK_CANARY & IMM12_MASK]
+#elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO)
+       ldr     r7, [r2, #TI_TASK]
 #endif
 #ifdef CONFIG_CPU_USE_DOMAINS
        mcr     p15, 0, r6, c3, c0, 0           @ Set domain register

@@ -776,6 +780,7 @@ ENTRY(__switch_to)
 #endif
  THUMB(        mov     ip, r4                     )
        mov     r0, r5
+       set_current r7
  ARM(  ldmia   r4, {r4 - sl, fp, sp, pc}  )
  THUMB(        ldmia   ip!, {r4 - sl, fp}         )
  THUMB(        ldr     sp, [ip], #4               )

and in the next one

@@ -765,7 +765,7 @@ ENTRY(__switch_to)
        .endif
        ldr     r7, [r7, #TSK_STACK_CANARY & IMM12_MASK]
 #elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO)
-       ldr     r7, [r2, #TI_TASK]
+       mov     r7, r2                          @ Preserve 'next'
 #endif
 #ifdef CONFIG_CPU_USE_DOMAINS
        mcr     p15, 0, r6, c3, c0, 0           @ Set domain register

Would that work for you?