On Wed, Mar 20, 2013 at 05:01:58PM -0700, Kevin Hilman wrote:
Add ARM support for the context tracking subsystem by instrumenting exception entry/exit points.
Special thanks to Mats Liljegren for testing, collaboration and adding support for exceptions/faults that were missing in early test versions.
Not sure all of these are a good idea or are correct...
@@ -405,7 +406,9 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) unsigned int instr; siginfo_t info; void __user *pc;
- enum ctx_state prev_state;
- prev_state = exception_enter(); pc = (void __user *)instruction_pointer(regs);
if (processor_mode(regs) == SVC_MODE) { @@ -433,8 +436,10 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) goto die_sig; }
- if (call_undef_hook(regs, instr) == 0)
- if (call_undef_hook(regs, instr) == 0) {
exception_exit(prev_state);- }
die_sig: #ifdef CONFIG_DEBUG_USER @@ -451,12 +456,17 @@ die_sig: info.si_addr = pc; arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6);
- exception_exit(prev_state);
So, FP emulation and VFP support happens via a separate path. Does this also need to be instrumented?
} asmlinkage void do_unexp_fiq (struct pt_regs *regs) {
- enum ctx_state prev_state;
- prev_state = exception_enter(); printk("Hmm. Unexpected FIQ received, but trying to continue\n"); printk("You may have a hardware problem...\n");
- exception_exit(prev_state);
Not a good idea. If we get here chances are things are really broken.
} /* @@ -467,6 +477,9 @@ asmlinkage void do_unexp_fiq (struct pt_regs *regs) */ asmlinkage void bad_mode(struct pt_regs *regs, int reason) {
- enum ctx_state prev_state;
- prev_state = exception_enter(); console_verbose();
printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]);
Same here. If we get here, we're probably about to die a horrid death.
@@ -746,7 +759,9 @@ baddataabort(int code, unsigned long instr, struct pt_regs *regs) { unsigned long addr = instruction_pointer(regs); siginfo_t info;
- enum ctx_state prev_state;
- prev_state = exception_enter();
#ifdef CONFIG_DEBUG_USER if (user_debug & UDBG_BADABORT) { printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", @@ -762,6 +777,7 @@ baddataabort(int code, unsigned long instr, struct pt_regs *regs) info.si_addr = (void __user *)addr; arm_notify_die("unknown data abort code", regs, &info, instr, 0);
- exception_exit(prev_state);
} void __readwrite_bug(const char *fn) diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 5dbf13f..759b70d 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -19,6 +19,7 @@ #include <linux/sched.h> #include <linux/highmem.h> #include <linux/perf_event.h> +#include <linux/context_tracking.h> #include <asm/exception.h> #include <asm/pgtable.h> @@ -424,9 +425,15 @@ do_translation_fault(unsigned long addr, unsigned int fsr, pgd_t *pgd, *pgd_k; pud_t *pud, *pud_k; pmd_t *pmd, *pmd_k;
- if (addr < TASK_SIZE)
return do_page_fault(addr, fsr, regs);
- enum ctx_state prev_state;
- prev_state = exception_enter();
- if (addr < TASK_SIZE) {
int ret;ret = do_page_fault(addr, fsr, regs);exception_exit(prev_state);return ret;- }
if (user_mode(regs)) goto bad_area; @@ -472,10 +479,12 @@ do_translation_fault(unsigned long addr, unsigned int fsr, goto bad_area; copy_pmd(pmd, pmd_k);
- exception_exit(prev_state); return 0;
bad_area: do_bad_area(addr, fsr, regs);
- exception_exit(prev_state); return 0;
} #else /* CONFIG_MMU */ @@ -494,7 +503,12 @@ do_translation_fault(unsigned long addr, unsigned int fsr, static int do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) {
- enum ctx_state prev_state;
- prev_state = exception_enter(); do_bad_area(addr, fsr, regs);
- exception_exit(prev_state);
- return 0;
} @@ -542,9 +556,11 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { const struct fsr_info *inf = fsr_info + fsr_fs(fsr); struct siginfo info;
- enum ctx_state prev_state;
- prev_state = exception_enter(); if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
return;
goto out;printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n", inf->name, fsr, addr); @@ -554,6 +570,8 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs) info.si_code = inf->code; info.si_addr = (void __user *)addr; arm_notify_die("", regs, &info, fsr, 0); +out:
- exception_exit(prev_state);
} void __init @@ -574,9 +592,11 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs) { const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr); struct siginfo info;
- enum ctx_state prev_state;
- prev_state = exception_enter(); if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
return;
goto out;printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n", inf->name, ifsr, addr); @@ -586,6 +606,8 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs) info.si_code = inf->code; info.si_addr = (void __user *)addr; arm_notify_die("", regs, &info, ifsr, 0); +out:
- exception_exit(prev_state);
} #ifndef CONFIG_ARM_LPAE
What is the reason for putting all this in the individual functions and not in the prefetch/data abort handlers - do_PrefetchAbort()/do_DataAbort()?