Redo RM9000 workaround which along with other DSP ASE changes was

causing some headache for debuggers knowing about signal frames.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/signal-common.h

@@ -160,7 +160,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
 static inline void *
 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
 {
-	unsigned long sp, almask;
+	unsigned long sp;
 
 	/* Default to using normal stack */
 	sp = regs->regs[29];
@@ -176,10 +176,32 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
 	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 		sp = current->sas_ss_sp + current->sas_ss_size;
 
-	if (PLAT_TRAMPOLINE_STUFF_LINE)
-		almask = ~(PLAT_TRAMPOLINE_STUFF_LINE - 1);
-	else
-		almask = ALMASK;
+	return (void *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? 32 : ALMASK));
+}
+
+static inline int install_sigtramp(unsigned int __user *tramp,
+	unsigned int syscall)
+{
+	int err;
 
-	return (void *)((sp - frame_size) & almask);
+	/*
+	 * Set up the return code ...
+	 *
+	 *         li      v0, __NR__foo_sigreturn
+	 *         syscall
+	 */
+
+	err = __put_user(0x24020000 + syscall, tramp + 0);
+	err |= __put_user(0x0000000c          , tramp + 1);
+	if (ICACHE_REFILLS_WORKAROUND_WAR) {
+		err |= __put_user(0, tramp + 2);
+		err |= __put_user(0, tramp + 3);
+		err |= __put_user(0, tramp + 4);
+		err |= __put_user(0, tramp + 5);
+		err |= __put_user(0, tramp + 6);
+		err |= __put_user(0, tramp + 7);
+	}
+	flush_cache_sigtramp((unsigned long) tramp);
+
+	return err;
 }

arch/mips/kernel/signal.c

@@ -8,6 +8,7 @@
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  */
 #include <linux/config.h>
+#include <linux/cache.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/personality.h>
@@ -30,6 +31,7 @@
 #include <asm/uaccess.h>
 #include <asm/ucontext.h>
 #include <asm/cpu-features.h>
+#include <asm/war.h>
 
 #include "signal-common.h"
 
@@ -157,26 +159,39 @@ asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 	return do_sigaltstack(uss, uoss, usp);
 }
 
-#if PLAT_TRAMPOLINE_STUFF_LINE
-#define __tramp __attribute__((aligned(PLAT_TRAMPOLINE_STUFF_LINE)))
-#else
-#define __tramp
-#endif
-
+/*
+ * Horribly complicated - with the bloody RM9000 workarounds enabled
+ * the signal trampolines is moving to the end of the structure so we can
+ * increase the alignment without breaking software compatibility.
+ */
 #ifdef CONFIG_TRAD_SIGNALS
 struct sigframe {
 	u32 sf_ass[4];			/* argument save space for o32 */
-	u32 sf_code[2] __tramp;		/* signal trampoline */
-	struct sigcontext sf_sc __tramp;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 sf_pad[2];
+#else
+	u32 sf_code[2];			/* signal trampoline */
+#endif
+	struct sigcontext sf_sc;
 	sigset_t sf_mask;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 sf_code[8] ____cacheline_aligned;	/* signal trampoline */
+#endif
 };
 #endif
 
 struct rt_sigframe {
 	u32 rs_ass[4];			/* argument save space for o32 */
-	u32 rs_code[2] __tramp;		/* signal trampoline */
-	struct siginfo rs_info __tramp;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_pad[2];
+#else
+	u32 rs_code[2];			/* signal trampoline */
+#endif
+	struct siginfo rs_info;
 	struct ucontext rs_uc;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_code[8] ____cacheline_aligned;	/* signal trampoline */
+#endif
 };
 
 #ifdef CONFIG_TRAD_SIGNALS
@@ -273,17 +288,7 @@ void setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 		goto give_sigsegv;
 
-	/*
-	 * Set up the return code ...
-	 *
-	 *         li      v0, __NR_sigreturn
-	 *         syscall
-	 */
-	if (PLAT_TRAMPOLINE_STUFF_LINE)
-		__clear_user(frame->sf_code, PLAT_TRAMPOLINE_STUFF_LINE);
-	err |= __put_user(0x24020000 + __NR_sigreturn, frame->sf_code + 0);
-	err |= __put_user(0x0000000c                 , frame->sf_code + 1);
-	flush_cache_sigtramp((unsigned long) frame->sf_code);
+	install_sigtramp(frame->sf_code, __NR_sigreturn);
 
 	err |= setup_sigcontext(regs, &frame->sf_sc);
 	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
@@ -329,17 +334,7 @@ void setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 		goto give_sigsegv;
 
-	/*
-	 * Set up the return code ...
-	 *
-	 *         li      v0, __NR_rt_sigreturn
-	 *         syscall
-	 */
-	if (PLAT_TRAMPOLINE_STUFF_LINE)
-		__clear_user(frame->rs_code, PLAT_TRAMPOLINE_STUFF_LINE);
-	err |= __put_user(0x24020000 + __NR_rt_sigreturn, frame->rs_code + 0);
-	err |= __put_user(0x0000000c                    , frame->rs_code + 1);
-	flush_cache_sigtramp((unsigned long) frame->rs_code);
+	install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
 
 	/* Create siginfo.  */
 	err |= copy_siginfo_to_user(&frame->rs_info, info);

arch/mips/kernel/signal32.c

@@ -7,6 +7,7 @@
  * Copyright (C) 1994 - 2000  Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  */
+#include <linux/cache.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
@@ -30,6 +31,7 @@
 #include <asm/ucontext.h>
 #include <asm/system.h>
 #include <asm/fpu.h>
+#include <asm/war.h>
 
 #define SI_PAD_SIZE32   ((SI_MAX_SIZE/sizeof(int)) - 3)
 
@@ -392,16 +394,30 @@ static int restore_sigcontext32(struct pt_regs *regs, struct sigcontext32 *sc)
 
 struct sigframe {
 	u32 sf_ass[4];			/* argument save space for o32 */
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 sf_pad[2];
+#else
 	u32 sf_code[2];			/* signal trampoline */
+#endif
 	struct sigcontext32 sf_sc;
 	sigset_t sf_mask;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 sf_code[8] ____cacheline_aligned;	/* signal trampoline */
+#endif
 };
 
 struct rt_sigframe32 {
 	u32 rs_ass[4];			/* argument save space for o32 */
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_pad[2];
+#else
 	u32 rs_code[2];			/* signal trampoline */
+#endif
 	compat_siginfo_t rs_info;
 	struct ucontext32 rs_uc;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_code[8] __attribute__((aligned(32)));	/* signal trampoline */
+#endif
 };
 
 int copy_siginfo_to_user32(compat_siginfo_t *to, siginfo_t *from)

arch/mips/kernel/signal_n32.c

@@ -15,6 +15,8 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
+#include <linux/cache.h>
+#include <linux/sched.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
@@ -36,6 +38,7 @@
 #include <asm/system.h>
 #include <asm/fpu.h>
 #include <asm/cpu-features.h>
+#include <asm/war.h>
 
 #include "signal-common.h"
 
@@ -62,17 +65,18 @@ struct ucontextn32 {
 	sigset_t            uc_sigmask;   /* mask last for extensibility */
 };
 
-#if PLAT_TRAMPOLINE_STUFF_LINE
-#define __tramp __attribute__((aligned(PLAT_TRAMPOLINE_STUFF_LINE)))
-#else
-#define __tramp
-#endif
-
 struct rt_sigframe_n32 {
 	u32 rs_ass[4];			/* argument save space for o32 */
-	u32 rs_code[2] __tramp;		/* signal trampoline */
-	struct siginfo rs_info __tramp;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_pad[2];
+#else
+	u32 rs_code[2];			/* signal trampoline */
+#endif
+	struct siginfo rs_info;
 	struct ucontextn32 rs_uc;
+#if ICACHE_REFILLS_WORKAROUND_WAR
+	u32 rs_code[8] ____cacheline_aligned;		/* signal trampoline */
+#endif
 };
 
 save_static_function(sysn32_rt_sigreturn);
@@ -137,17 +141,7 @@ void setup_rt_frame_n32(struct k_sigaction * ka,
 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 		goto give_sigsegv;
 
-	/*
-	 * Set up the return code ...
-	 *
-	 *         li      v0, __NR_rt_sigreturn
-	 *         syscall
-	 */
-	if (PLAT_TRAMPOLINE_STUFF_LINE)
-		__clear_user(frame->rs_code, PLAT_TRAMPOLINE_STUFF_LINE);
-	err |= __put_user(0x24020000 + __NR_N32_rt_sigreturn, frame->rs_code + 0);
-	err |= __put_user(0x0000000c                        , frame->rs_code + 1);
-	flush_cache_sigtramp((unsigned long) frame->rs_code);
+	install_sigtramp(frame->rs_code, __NR_N32_rt_sigreturn);
 
 	/* Create siginfo.  */
 	err |= copy_siginfo_to_user(&frame->rs_info, info);

include/asm-mips/cpu-features.h

@@ -109,17 +109,6 @@
 #define cpu_has_dsp		(cpu_data[0].ases & MIPS_ASE_DSP)
 #endif
 
-/*
- * Certain CPUs may throw bizarre exceptions if not the whole cacheline
- * contains valid instructions.  For these we ensure proper alignment of
- * signal trampolines and pad them to the size of a full cache lines with
- * nops.  This is also used in structure definitions so can't be a test macro
- * like the others.
- */
-#ifndef PLAT_TRAMPOLINE_STUFF_LINE
-#define PLAT_TRAMPOLINE_STUFF_LINE	0UL
-#endif
-
 #ifdef CONFIG_32BIT
 # ifndef cpu_has_nofpuex
 # define cpu_has_nofpuex	(cpu_data[0].options & MIPS_CPU_NOFPUEX)

include/asm-mips/mach-ja/cpu-feature-overrides.h

@@ -37,10 +37,4 @@
 #define cpu_icache_line_size()	32
 #define cpu_scache_line_size()	32
 
-/*
- * On the RM9000 we need to ensure that I-cache lines being fetches only
- * contain valid instructions are funny things will happen.
- */
-#define PLAT_TRAMPOLINE_STUFF_LINE	32UL
-
 #endif /* __ASM_MACH_JA_CPU_FEATURE_OVERRIDES_H */

include/asm-mips/mach-ocelot3/cpu-feature-overrides.h

@@ -40,10 +40,4 @@
 #define cpu_icache_line_size()	32
 #define cpu_scache_line_size()	32
 
-/*
- * On the RM9000 we need to ensure that I-cache lines being fetches only
- * contain valid instructions are funny things will happen.
- */
-#define PLAT_TRAMPOLINE_STUFF_LINE	32UL
-
 #endif /* __ASM_MACH_JA_CPU_FEATURE_OVERRIDES_H */

include/asm-mips/mach-yosemite/cpu-feature-overrides.h

@@ -37,10 +37,4 @@
 #define cpu_icache_line_size()	32
 #define cpu_scache_line_size()	32
 
-/*
- * On the RM9000 we need to ensure that I-cache lines being fetches only
- * contain valid instructions are funny things will happen.
- */
-#define PLAT_TRAMPOLINE_STUFF_LINE	32UL
-
 #endif /* __ASM_MACH_YOSEMITE_CPU_FEATURE_OVERRIDES_H */

include/asm-mips/war.h

@@ -176,6 +176,17 @@
 #define  RM9000_CDEX_SMP_WAR		1
 #endif
 
+/*
+ * The RM9000 has a bug (though PMC-Sierra opposes it being called that)
+ * where invalid instructions in the same I-cache line worth of instructions
+ * being fetched may case spurious exceptions.
+ */
+#if defined(CONFIG_MOMENCO_JAGUAR_ATX) || defined(CONFIG_MOMENCO_OCELOT_3) || \
+    defined(CONFIG_PMC_YOSEMITE)
+#define ICACHE_REFILLS_WORKAROUND_WAR	1
+#endif
+
+
 /*
  * ON the R10000 upto version 2.6 (not sure about 2.7) there is a bug that
  * may cause ll / sc and lld / scd sequences to execute non-atomically.
@@ -187,6 +198,9 @@
 /*
  * Workarounds default to off
  */
+#ifndef ICACHE_REFILLS_WORKAROUND_WAR
+#define ICACHE_REFILLS_WORKAROUND_WAR	0
+#endif
 #ifndef R4600_V1_INDEX_ICACHEOP_WAR
 #define R4600_V1_INDEX_ICACHEOP_WAR	0
 #endif