sh: wire up SET/GET_UNALIGN_CTL.

This hooks up the SET/GET_UNALIGN_CTL knobs cribbing the bulk of it from the PPC and ia64 implementations. The thread flags happen to be the logical inverse of what the global fault mode is set to, so this works out pretty cleanly. By default the global fault mode is used, with tasks now being able to override their own settings via prctl(). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
git-mirror · Feb 23, 2010 · 94ea5e4 · 94ea5e4
1 parent 7c1b2c6
commit 94ea5e4
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Showing 4 changed files with 51 additions and 2 deletions.
diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
@@ -107,13 +107,25 @@ extern unsigned int xstate_size;
 extern void free_thread_xstate(struct task_struct *);
 extern struct kmem_cache *task_xstate_cachep;
 
+/* arch/sh/mm/alignment.c */
+extern int get_unalign_ctl(struct task_struct *, unsigned long addr);
+extern int set_unalign_ctl(struct task_struct *, unsigned int val);
+
+#define GET_UNALIGN_CTL(tsk, addr)	get_unalign_ctl((tsk), (addr))
+#define SET_UNALIGN_CTL(tsk, val)	set_unalign_ctl((tsk), (val))
+
 /* arch/sh/mm/init.c */
 extern unsigned int mem_init_done;
 
 /* arch/sh/kernel/setup.c */
 const char *get_cpu_subtype(struct sh_cpuinfo *c);
 extern const struct seq_operations cpuinfo_op;
 
+/* thread_struct flags */
+#define SH_THREAD_UAC_NOPRINT	(1 << 0)
+#define SH_THREAD_UAC_SIGBUS	(1 << 1)
+#define SH_THREAD_UAC_MASK	(SH_THREAD_UAC_NOPRINT | SH_THREAD_UAC_SIGBUS)
+
 /* processor boot mode configuration */
 #define MODE_PIN0 (1 << 0)
 #define MODE_PIN1 (1 << 1)

diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
@@ -101,8 +101,11 @@ struct thread_struct {
 	unsigned long sp;
 	unsigned long pc;
 
+	/* Various thread flags, see SH_THREAD_xxx */
+	unsigned long flags;
+
 	/* Save middle states of ptrace breakpoints */
-	struct perf_event	*ptrace_bps[HBP_NUM];
+	struct perf_event *ptrace_bps[HBP_NUM];
 
 #ifdef CONFIG_SH_DSP
 	/* Dsp status information */
@@ -115,6 +118,7 @@ struct thread_struct {
 
 #define INIT_THREAD  {						\
 	.sp = sizeof(init_stack) + (long) &init_stack,		\
+	.flags = 0,						\
 }
 
 /* Forward declaration, a strange C thing */

diff --git a/arch/sh/include/asm/processor_64.h b/arch/sh/include/asm/processor_64.h
@@ -108,6 +108,10 @@ union thread_xstate {
 struct thread_struct {
 	unsigned long sp;
 	unsigned long pc;
+
+	/* Various thread flags, see SH_THREAD_xxx */
+	unsigned long flags;
+
 	/* This stores the address of the pt_regs built during a context
 	   switch, or of the register save area built for a kernel mode
 	   exception.  It is used for backtracing the stack of a sleeping task
@@ -138,6 +142,7 @@ struct thread_struct {
 	.trap_no	= 0,			\
 	.error_code	= 0,			\
 	.address	= 0,			\
+	.flags		= 0,			\
 }
 
 /*

diff --git a/arch/sh/mm/alignment.c b/arch/sh/mm/alignment.c
@@ -14,6 +14,7 @@
 #include <linux/proc_fs.h>
 #include <linux/uaccess.h>
 #include <asm/alignment.h>
+#include <asm/processor.h>
 
 static unsigned long se_user;
 static unsigned long se_sys;
@@ -59,9 +60,36 @@ void inc_unaligned_kernel_access(void)
 	se_sys++;
 }
 
+/*
+ * This defaults to the global policy which can be set from the command
+ * line, while processes can overload their preferences via prctl().
+ */
 unsigned int unaligned_user_action(void)
 {
-	return se_usermode;
+	unsigned int action = se_usermode;
+
+	if (current->thread.flags & SH_THREAD_UAC_SIGBUS) {
+		action &= ~UM_FIXUP;
+		action |= UM_SIGNAL;
+	}
+
+	if (current->thread.flags & SH_THREAD_UAC_NOPRINT)
+		action &= ~UM_WARN;
+
+	return action;
+}
+
+int get_unalign_ctl(struct task_struct *tsk, unsigned long addr)
+{
+	return put_user(tsk->thread.flags & SH_THREAD_UAC_MASK,
+			(unsigned int __user *)addr);
+}
+
+int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
+{
+	tsk->thread.flags = (tsk->thread.flags & ~SH_THREAD_UAC_MASK) |
+			    (val & SH_THREAD_UAC_MASK);
+	return 0;
 }
 
 void unaligned_fixups_notify(struct task_struct *tsk, insn_size_t insn,