[MIPS] Fast path for rdhwr emulation for TLS
Add special short path for emulationg RDHWR which is used to support TLS.
Add an extra prologue for cpu_has_vtag_icache case.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 5baca16..aacd4a0 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -19,6 +19,7 @@
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/war.h>
+#include <asm/page.h>
#define PANIC_PIC(msg) \
.set push; \
@@ -378,6 +379,68 @@
BUILD_HANDLER dsp dsp sti silent /* #26 */
BUILD_HANDLER reserved reserved sti verbose /* others */
+ .align 5
+ LEAF(handle_ri_rdhwr_vivt)
+#ifdef CONFIG_MIPS_MT_SMTC
+ PANIC_PIC("handle_ri_rdhwr_vivt called")
+#else
+ .set push
+ .set noat
+ .set noreorder
+ /* check if TLB contains a entry for EPC */
+ MFC0 k1, CP0_ENTRYHI
+ andi k1, 0xff /* ASID_MASK */
+ MFC0 k0, CP0_EPC
+ PTR_SRL k0, PAGE_SHIFT + 1
+ PTR_SLL k0, PAGE_SHIFT + 1
+ or k1, k0
+ MTC0 k1, CP0_ENTRYHI
+ mtc0_tlbw_hazard
+ tlbp
+ tlb_probe_hazard
+ mfc0 k1, CP0_INDEX
+ .set pop
+ bltz k1, handle_ri /* slow path */
+ /* fall thru */
+#endif
+ END(handle_ri_rdhwr_vivt)
+
+ LEAF(handle_ri_rdhwr)
+ .set push
+ .set noat
+ .set noreorder
+ /* 0x7c03e83b: rdhwr v1,$29 */
+ MFC0 k1, CP0_EPC
+ lui k0, 0x7c03
+ lw k1, (k1)
+ ori k0, 0xe83b
+ .set reorder
+ bne k0, k1, handle_ri /* if not ours */
+ /* The insn is rdhwr. No need to check CAUSE.BD here. */
+ get_saved_sp /* k1 := current_thread_info */
+ .set noreorder
+ MFC0 k0, CP0_EPC
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+ ori k1, _THREAD_MASK
+ xori k1, _THREAD_MASK
+ LONG_L v1, TI_TP_VALUE(k1)
+ LONG_ADDIU k0, 4
+ jr k0
+ rfe
+#else
+ LONG_ADDIU k0, 4 /* stall on $k0 */
+ MTC0 k0, CP0_EPC
+ /* I hope three instructions between MTC0 and ERET are enough... */
+ ori k1, _THREAD_MASK
+ xori k1, _THREAD_MASK
+ LONG_L v1, TI_TP_VALUE(k1)
+ .set mips3
+ eret
+ .set mips0
+#endif
+ .set pop
+ END(handle_ri_rdhwr)
+
#ifdef CONFIG_64BIT
/* A temporary overflow handler used by check_daddi(). */