sparc32: Implement hard_smp_processor_id() via instruction patching.

This is the last non-trivial user of btfixup.

Like sparc64, use a special patch section to resolve the various
implementations of how to read the current CPU's ID when we don't
have current_thread_info()->cpu necessarily available.

Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 18 insertions, 31 deletions

diff --git a/arch/sparc/include/asm/winmacro.h b/arch/sparc/include/asm/winmacro.h
index a9be04b0d049..9b7b21764cde 100644
--- a/arch/sparc/include/asm/winmacro.h
+++ b/arch/sparc/include/asm/winmacro.h
@@ -103,37 +103,24 @@
         st       %scratch, [%cur_reg + TI_W_SAVED];
 
 #ifdef CONFIG_SMP
-/* Results of LOAD_CURRENT() after BTFIXUP for SUN4M, SUN4D & LEON (comments) */
-#define LOAD_CURRENT4M(dest_reg, idreg) \
-        rd       %tbr, %idreg; \
-        sethi    %hi(current_set), %dest_reg; \
-        srl      %idreg, 10, %idreg; \
-        or       %dest_reg, %lo(current_set), %dest_reg; \
-        and      %idreg, 0xc, %idreg; \
-        ld       [%idreg + %dest_reg], %dest_reg;
-
-#define LOAD_CURRENT4D(dest_reg, idreg) \
-        lda      [%g0] ASI_M_VIKING_TMP1, %idreg; \
-        sethi   %hi(C_LABEL(current_set)), %dest_reg; \
-        sll     %idreg, 2, %idreg; \
-        or      %dest_reg, %lo(C_LABEL(current_set)), %dest_reg; \
-        ld      [%idreg + %dest_reg], %dest_reg;
-
-#define LOAD_CURRENT_LEON(dest_reg, idreg)                      \
-        rd      %asr17, %idreg;                                 \
-        sethi   %hi(current_set), %dest_reg;                    \
-        srl     %idreg, 0x1c, %idreg;                           \
-        or      %dest_reg, %lo(current_set), %dest_reg;         \
-        sll     %idreg, 0x2, %idreg;                            \
-        ld      [%idreg + %dest_reg], %dest_reg;
-
-/* Blackbox - take care with this... - check smp4m and smp4d before changing this. */
-#define LOAD_CURRENT(dest_reg, idreg)                                   \
-        sethi    %hi(___b_load_current), %idreg;                        \
-        sethi    %hi(current_set), %dest_reg;                   \
-        sethi    %hi(boot_cpu_id4), %idreg;                     \
-        or       %dest_reg, %lo(current_set), %dest_reg;        \
-        ldub     [%idreg + %lo(boot_cpu_id4)], %idreg;          \
+#define LOAD_CURRENT(dest_reg, idreg)                   \
+661:    rd      %tbr, %idreg;                           \
+        srl     %idreg, 10, %idreg;                     \
+        and     %idreg, 0xc, %idreg;                    \
+        .section        .cpuid_patch, "ax";             \
+        /* Instruction location. */                     \
+        .word           661b;                           \
+        /* SUN4D implementation. */                     \
+        lda      [%g0] ASI_M_VIKING_TMP1, %idreg;       \
+        sll      %idreg, 2, %idreg;                     \
+        nop;                                            \
+        /* LEON implementation. */                      \
+        rd      %asr17, %idreg;                         \
+        srl     %idreg, 0x1c, %idreg;                   \
+        sll     %idreg, 0x02, %idreg;                   \
+        .previous;                                      \
+        sethi    %hi(current_set), %dest_reg;           \
+        or       %dest_reg, %lo(current_set), %dest_reg;\
         ld       [%idreg + %dest_reg], %dest_reg;
 #else
 #define LOAD_CURRENT(dest_reg, idreg) \