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sh: Wire up division and address error exceptions on SH-2A.
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SH-2A has special division hardware as opposed to a full-fledged FPU,
wire up the exception handlers for this.

Signed-off-by: Yoshinori Sato <[email protected]>
Signed-off-by: Paul Mundt <[email protected]>
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@ysat0 @pmundt
ysat0 authored and pmundt committed Dec 6, 2006
1 parent 9d4436a commit 0983b31
Showing 1 changed file with 79 additions and 9 deletions.
88 changes: 79 additions & 9 deletions arch/sh/kernel/traps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,8 +33,13 @@
#endif

#ifdef CONFIG_CPU_SH2
#define TRAP_RESERVED_INST 4
#define TRAP_ILLEGAL_SLOT_INST 6
# define TRAP_RESERVED_INST 4
# define TRAP_ILLEGAL_SLOT_INST 6
# define TRAP_ADDRESS_ERROR 9
# ifdef CONFIG_CPU_SH2A
# define TRAP_DIVZERO_ERROR 17
# define TRAP_DIVOVF_ERROR 18
# endif
#else
#define TRAP_RESERVED_INST 12
#define TRAP_ILLEGAL_SLOT_INST 13
Expand Down Expand Up @@ -479,31 +484,52 @@ static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
return ret;
}

#ifdef CONFIG_CPU_HAS_SR_RB
#define lookup_exception_vector(x) \
__asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))
#else
#define lookup_exception_vector(x) \
__asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))
#endif

/*
* Handle various address error exceptions
*/
asmlinkage void do_address_error(struct pt_regs *regs,
unsigned long writeaccess,
unsigned long address)
{
unsigned long error_code;
unsigned long error_code = 0;
mm_segment_t oldfs;
u16 instruction;
int tmp;

asm volatile("stc r2_bank,%0": "=r" (error_code));
/* Intentional ifdef */
#ifdef CONFIG_CPU_HAS_SR_RB
lookup_exception_vector(error_code);
#endif

oldfs = get_fs();

if (user_mode(regs)) {
local_irq_enable();
current->thread.error_code = error_code;
#ifdef CONFIG_CPU_SH2
/*
* On the SH-2, we only have a single vector for address
* errors, there's no differentiating between a load error
* and a store error.
*/
current->thread.trap_no = 9;
#else
current->thread.trap_no = (writeaccess) ? 8 : 7;
#endif

/* bad PC is not something we can fix */
if (regs->pc & 1)
goto uspace_segv;

#ifndef CONFIG_CPU_SH2A
set_fs(USER_DS);
if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
/* Argh. Fault on the instruction itself.
Expand All @@ -518,6 +544,7 @@ asmlinkage void do_address_error(struct pt_regs *regs,

if (tmp==0)
return; /* sorted */
#endif

uspace_segv:
printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);
Expand All @@ -526,6 +553,7 @@ asmlinkage void do_address_error(struct pt_regs *regs,
if (regs->pc & 1)
die("unaligned program counter", regs, error_code);

#ifndef CONFIG_CPU_SH2A
set_fs(KERNEL_DS);
if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
/* Argh. Fault on the instruction itself.
Expand All @@ -537,6 +565,10 @@ asmlinkage void do_address_error(struct pt_regs *regs,

handle_unaligned_access(instruction, regs);
set_fs(oldfs);
#else
printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);
force_sig(SIGSEGV, current);
#endif
}
}

Expand Down Expand Up @@ -569,6 +601,29 @@ int is_dsp_inst(struct pt_regs *regs)
#define is_dsp_inst(regs) (0)
#endif /* CONFIG_SH_DSP */

#ifdef CONFIG_CPU_SH2A
asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
siginfo_t info;

current->thread.trap_no = r4;
current->thread.error_code = 0;

switch (r4) {
case TRAP_DIVZERO_ERROR:
info.si_code = FPE_INTDIV;
break;
case TRAP_DIVOVF_ERROR:
info.si_code = FPE_INTOVF;
break;
}

force_sig_info(SIGFPE, &info, current);
}
#endif

/* arch/sh/kernel/cpu/sh4/fpu.c */
extern int do_fpu_inst(unsigned short, struct pt_regs *);
extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5,
Expand All @@ -582,7 +637,7 @@ asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
struct task_struct *tsk = current;

#ifdef CONFIG_SH_FPU_EMU
unsigned short inst;
unsigned short inst = 0;
int err;

get_user(inst, (unsigned short*)regs.pc);
Expand All @@ -604,7 +659,8 @@ asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
}
#endif

asm volatile("stc r2_bank, %0": "=r" (error_code));
lookup_exception_vector(error_code);

local_irq_enable();
tsk->thread.error_code = error_code;
tsk->thread.trap_no = TRAP_RESERVED_INST;
Expand Down Expand Up @@ -663,7 +719,7 @@ asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
unsigned long error_code;
struct task_struct *tsk = current;
#ifdef CONFIG_SH_FPU_EMU
unsigned short inst;
unsigned short inst = 0;

get_user(inst, (unsigned short *)regs.pc + 1);
if (!do_fpu_inst(inst, &regs)) {
Expand All @@ -675,7 +731,8 @@ asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
/* not a FPU inst. */
#endif

asm volatile("stc r2_bank, %0": "=r" (error_code));
lookup_exception_vector(error_code);

local_irq_enable();
tsk->thread.error_code = error_code;
tsk->thread.trap_no = TRAP_RESERVED_INST;
Expand All @@ -689,7 +746,8 @@ asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
struct pt_regs regs)
{
long ex;
asm volatile("stc r2_bank, %0" : "=r" (ex));

lookup_exception_vector(ex);
die_if_kernel("exception", &regs, ex);
}

Expand Down Expand Up @@ -741,6 +799,10 @@ void *set_exception_table_vec(unsigned int vec, void *handler)
return old_handler;
}

extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs);

void __init trap_init(void)
{
set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
Expand All @@ -759,6 +821,14 @@ void __init trap_init(void)
set_exception_table_evt(0x800, do_fpu_state_restore);
set_exception_table_evt(0x820, do_fpu_state_restore);
#endif

#ifdef CONFIG_CPU_SH2
set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler);
#endif
#ifdef CONFIG_CPU_SH2A
set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
#endif

/* Setup VBR for boot cpu */
per_cpu_trap_init();
Expand Down

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