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authorTakashi YOSHII <takasi-y@ops.dti.ne.jp>2006-09-27 17:15:32 +0900
committerPaul Mundt <lethal@linux-sh.org>2006-09-27 17:15:32 +0900
commit4b565680d16300acab0ff167e24f0ea289a6bd5d (patch)
treed233188a29c0a0ccfdf72c84899e926df2fc2ba8 /arch/sh/kernel
parent317a6104a99f87c0b35c0d9f19ec23ee7429b33e (diff)
downloadlwn-4b565680d16300acab0ff167e24f0ea289a6bd5d.tar.gz
lwn-4b565680d16300acab0ff167e24f0ea289a6bd5d.zip
sh: math-emu support
This implements initial math-emu support, aimed primarily at SH-3. Signed-off-by: Takashi YOSHII <takasi-y@ops.dti.ne.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel')
-rw-r--r--arch/sh/kernel/traps.c164
1 files changed, 125 insertions, 39 deletions
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 21bef1b5f991..95c810b3c97e 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -36,40 +36,15 @@
#ifdef CONFIG_SH_KGDB
#include <asm/kgdb.h>
-#define CHK_REMOTE_DEBUG(regs) \
-{ \
- if ((kgdb_debug_hook != (kgdb_debug_hook_t *) NULL) && (!user_mode(regs))) \
- { \
- (*kgdb_debug_hook)(regs); \
- } \
+#define CHK_REMOTE_DEBUG(regs) \
+{ \
+ if (kgdb_debug_hook && !user_mode(regs))\
+ (*kgdb_debug_hook)(regs); \
}
#else
#define CHK_REMOTE_DEBUG(regs)
#endif
-#define DO_ERROR(trapnr, signr, str, name, tsk) \
-asmlinkage void do_##name(unsigned long r4, unsigned long r5, \
- unsigned long r6, unsigned long r7, \
- struct pt_regs regs) \
-{ \
- unsigned long error_code; \
- \
- /* Check if it's a DSP instruction */ \
- if (is_dsp_inst(&regs)) { \
- /* Enable DSP mode, and restart instruction. */ \
- regs.sr |= SR_DSP; \
- return; \
- } \
- \
- asm volatile("stc r2_bank, %0": "=r" (error_code)); \
- local_irq_enable(); \
- tsk->thread.error_code = error_code; \
- tsk->thread.trap_no = trapnr; \
- CHK_REMOTE_DEBUG(&regs); \
- force_sig(signr, tsk); \
- die_if_no_fixup(str,&regs,error_code); \
-}
-
#ifdef CONFIG_CPU_SH2
#define TRAP_RESERVED_INST 4
#define TRAP_ILLEGAL_SLOT_INST 6
@@ -575,8 +550,117 @@ int is_dsp_inst(struct pt_regs *regs)
#define is_dsp_inst(regs) (0)
#endif /* CONFIG_SH_DSP */
-DO_ERROR(TRAP_RESERVED_INST, SIGILL, "reserved instruction", reserved_inst, current)
-DO_ERROR(TRAP_ILLEGAL_SLOT_INST, SIGILL, "illegal slot instruction", illegal_slot_inst, current)
+extern int do_fpu_inst(unsigned short, struct pt_regs*);
+
+asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
+ unsigned long r6, unsigned long r7,
+ struct pt_regs regs)
+{
+ unsigned long error_code;
+ struct task_struct *tsk = current;
+
+#ifdef CONFIG_SH_FPU_EMU
+ unsigned short inst;
+ int err;
+
+ get_user(inst, (unsigned short*)regs.pc);
+
+ err = do_fpu_inst(inst, &regs);
+ if (!err) {
+ regs.pc += 2;
+ return;
+ }
+ /* not a FPU inst. */
+#endif
+
+#ifdef CONFIG_SH_DSP
+ /* Check if it's a DSP instruction */
+ if (is_dsp_inst(&regs)) {
+ /* Enable DSP mode, and restart instruction. */
+ regs.sr |= SR_DSP;
+ return;
+ }
+#endif
+
+ asm volatile("stc r2_bank, %0": "=r" (error_code));
+ local_irq_enable();
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = TRAP_RESERVED_INST;
+ CHK_REMOTE_DEBUG(&regs);
+ force_sig(SIGILL, tsk);
+ die_if_no_fixup("reserved instruction", &regs, error_code);
+}
+
+#ifdef CONFIG_SH_FPU_EMU
+static int emulate_branch(unsigned short inst, struct pt_regs* regs)
+{
+ /*
+ * bfs: 8fxx: PC+=d*2+4;
+ * bts: 8dxx: PC+=d*2+4;
+ * bra: axxx: PC+=D*2+4;
+ * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
+ * braf:0x23: PC+=Rn*2+4;
+ * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
+ * jmp: 4x2b: PC=Rn;
+ * jsr: 4x0b: PC=Rn after PR=PC+4;
+ * rts: 000b: PC=PR;
+ */
+ if ((inst & 0xfd00) == 0x8d00) {
+ regs->pc += SH_PC_8BIT_OFFSET(inst);
+ return 0;
+ }
+
+ if ((inst & 0xe000) == 0xa000) {
+ regs->pc += SH_PC_12BIT_OFFSET(inst);
+ return 0;
+ }
+
+ if ((inst & 0xf0df) == 0x0003) {
+ regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
+ return 0;
+ }
+
+ if ((inst & 0xf0df) == 0x400b) {
+ regs->pc = regs->regs[(inst & 0x0f00) >> 8];
+ return 0;
+ }
+
+ if ((inst & 0xffff) == 0x000b) {
+ regs->pc = regs->pr;
+ return 0;
+ }
+
+ return 1;
+}
+#endif
+
+asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
+ unsigned long r6, unsigned long r7,
+ struct pt_regs regs)
+{
+ unsigned long error_code;
+ struct task_struct *tsk = current;
+#ifdef CONFIG_SH_FPU_EMU
+ unsigned short inst;
+
+ get_user(inst, (unsigned short *)regs.pc + 1);
+ if (!do_fpu_inst(inst, &regs)) {
+ get_user(inst, (unsigned short *)regs.pc);
+ if (!emulate_branch(inst, &regs))
+ return;
+ /* fault in branch.*/
+ }
+ /* not a FPU inst. */
+#endif
+
+ asm volatile("stc r2_bank, %0": "=r" (error_code));
+ local_irq_enable();
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = TRAP_RESERVED_INST;
+ CHK_REMOTE_DEBUG(&regs);
+ force_sig(SIGILL, tsk);
+ die_if_no_fixup("illegal slot instruction", &regs, error_code);
+}
asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
@@ -634,14 +718,16 @@ void __init trap_init(void)
exception_handling_table[TRAP_ILLEGAL_SLOT_INST]
= (void *)do_illegal_slot_inst;
-#ifdef CONFIG_CPU_SH4
- if (!(cpu_data->flags & CPU_HAS_FPU)) {
- /* For SH-4 lacking an FPU, treat floating point instructions
- as reserved. */
- /* entry 64 corresponds to EXPEVT=0x800 */
- exception_handling_table[64] = (void *)do_reserved_inst;
- exception_handling_table[65] = (void *)do_illegal_slot_inst;
- }
+#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
+ defined(CONFIG_SH_FPU_EMU)
+ /*
+ * For SH-4 lacking an FPU, treat floating point instructions as
+ * reserved. They'll be handled in the math-emu case, or faulted on
+ * otherwise.
+ */
+ /* entry 64 corresponds to EXPEVT=0x800 */
+ exception_handling_table[64] = (void *)do_reserved_inst;
+ exception_handling_table[65] = (void *)do_illegal_slot_inst;
#endif
/* Setup VBR for boot cpu */