[PATCH x86/mm 01/11] x86-32 thread_struct.debugreg

Roland McGrath
2007-11-29T11:57:35Z

This replaces the debugreg[7] member of thread_struct with individual
members debugreg0, etc. This saves two words for the dummies 4 and 5,
and harmonizes the code between 32 and 64.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/x86/kernel/process_32.c | 31 ++++++++++++++++++++-----------
arch/x86/kernel/ptrace_32.c | 29 ++++++++++++++++++++++++-----
arch/x86/kernel/signal_32.c | 4 ++--
arch/x86/kernel/traps_32.c | 4 ++--
arch/x86/power/cpu.c | 14 +++++++-------
include/asm-x86/processor_32.h | 7 ++++++-
6 files changed, 61 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8234054..d37bf10 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -425,7 +425,12 @@ void flush_thread(void)
{
struct task_struct *tsk = current;

- memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
+ tsk->thread.debugreg0 = 0;
+ tsk->thread.debugreg1 = 0;
+ tsk->thread.debugreg2 = 0;
+ tsk->thread.debugreg3 = 0;
+ tsk->thread.debugreg6 = 0;
+ tsk->thread.debugreg7 = 0;
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
clear_tsk_thread_flag(tsk, TIF_DEBUG);
/*
@@ -502,7 +507,6 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
*/
void dump_thread(struct pt_regs * regs, struct user * dump)
{
- int i;
u16 gs;

/* changed the size calculations - should hopefully work better. lbt */
@@ -513,8 +517,14 @@ void dump_thread(struct pt_regs * regs, struct user * dump)
dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
dump->u_dsize -= dump->u_tsize;
dump->u_ssize = 0;
- for (i = 0; i < 8; i++)
- dump->u_debugreg[i] = current->thread.debugreg[i];
+ dump->u_debugreg[0] = current->thread.debugreg0;
+ dump->u_debugreg[1] = current->thread.debugreg1;
+ dump->u_debugreg[2] = current->thread.debugreg2;
+ dump->u_debugreg[3] = current->thread.debugreg3;
+ dump->u_debugreg[4] = 0;
+ dump->u_debugreg[5] = 0;
+ dump->u_debugreg[6] = current->thread.debugreg6;
+ dump->u_debugreg[7] = current->thread.debugreg7;

if (dump->start_stack < TASK_SIZE)
dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
@@ -592,13 +602,13 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
wrmsr(MSR_IA32_DEBUGCTLMSR, next->debugctlmsr, 0);

if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
- set_debugreg(next->debugreg[0], 0);
- set_debugreg(next->debugreg[1], 1);
- set_debugreg(next->debugreg[2], 2);
- set_debugreg(next->debugreg[3], 3);
+ set_debugreg(next->debugreg0, 0);
+ set_debugreg(next->debugreg1, 1);
+ set_debugreg(next->debugreg2, 2);
+ set_debugreg(next->debugreg3, 3);
/* no 4 and 5 */
- set_debugreg(next->debugreg[6], 6);
- set_debugreg(next->debugreg[7], 7);
+ set_debugreg(next->debugreg6, 6);
+ set_debugreg(next->debugreg7, 7);
}

#ifdef CONFIG_SECCOMP
@@ -849,4 +859,3 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
unsigned long range_end = mm->brk + 0x02000000;
return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
}
-
diff --git a/arch/x86/kernel/ptrace_32.c b/arch/x86/kernel/ptrace_32.c
index 2607130..fed83d0 100644
--- a/arch/x86/kernel/ptrace_32.c
+++ b/arch/x86/kernel/ptrace_32.c
@@ -133,19 +133,39 @@ static unsigned long getreg(struct task_struct *child, unsigned long regno)
*/
static unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
{
- return child->thread.debugreg[n];
+ switch (n) {
+ case 0: return child->thread.debugreg0;
+ case 1: return child->thread.debugreg1;
+ case 2: return child->thread.debugreg2;
+ case 3: return child->thread.debugreg3;
+ case 6: return child->thread.debugreg6;
+ case 7: return child->thread.debugreg7;
+ }
+ return 0;
}

static int ptrace_set_debugreg(struct task_struct *child,
int n, unsigned long data)
{
+ int i;
+
if (unlikely(n == 4 || n == 5))
return -EIO;

if (n < 4 && unlikely(data >= TASK_SIZE - 3))
return -EIO;

- if (n == 7) {
+ switch (n) {
+ case 0: child->thread.debugreg0 = data; break;
+ case 1: child->thread.debugreg1 = data; break;
+ case 2: child->thread.debugreg2 = data; break;
+ case 3: child->thread.debugreg3 = data; break;
+
+ case 6:
+ child->thread.debugreg6 = data;
+ break;
+
+ case 7:
/*
* Sanity-check data. Take one half-byte at once with
* check = (val >> (16 + 4*i)) & 0xf. It contains the
@@ -176,19 +196,18 @@ static int ptrace_set_debugreg(struct task_struct *child,
* 64-bit kernel), so the x86_64 mask value is 0x5454.
* See the AMD manual no. 24593 (AMD64 System Programming)
*/
- int i;
data &= ~DR_CONTROL_RESERVED;
for (i = 0; i < 4; i++)
if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
return -EIO;
+ child->thread.debugreg7 = data;
if (data)
set_tsk_thread_flag(child, TIF_DEBUG);
else
clear_tsk_thread_flag(child, TIF_DEBUG);
+ break;
}

- child->thread.debugreg[n] = data;
-
return 0;
}

diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index e8ab332..985c197 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -605,8 +605,8 @@ static void fastcall do_signal(struct pt_regs *regs)
* have been cleared if the watchpoint triggered
* inside the kernel.
*/
- if (unlikely(current->thread.debugreg[7]))
- set_debugreg(current->thread.debugreg[7], 7);
+ if (unlikely(current->thread.debugreg7))
+ set_debugreg(current->thread.debugreg7, 7);

/* Whee! Actually deliver the signal. */
if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index f34842a..7858ccb 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -853,7 +853,7 @@ fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)

/* Mask out spurious debug traps due to lazy DR7 setting */
if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
- if (!tsk->thread.debugreg[7])
+ if (!tsk->thread.debugreg7)
goto clear_dr7;
}

@@ -861,7 +861,7 @@ fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
goto debug_vm86;

/* Save debug status register where ptrace can see it */
- tsk->thread.debugreg[6] = condition;
+ tsk->thread.debugreg6 = condition;

/*
* Single-stepping through TF: make sure we ignore any events in
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 998fd3e..5a98dc3 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -74,14 +74,14 @@ static void fix_processor_context(void)
/*
* Now maybe reload the debug registers
*/
- if (current->thread.debugreg[7]){
- set_debugreg(current->thread.debugreg[0], 0);
- set_debugreg(current->thread.debugreg[1], 1);
- set_debugreg(current->thread.debugreg[2], 2);
- set_debugreg(current->thread.debugreg[3], 3);
+ if (current->thread.debugreg7) {
+ set_debugreg(current->thread.debugreg0, 0);
+ set_debugreg(current->thread.debugreg1, 1);
+ set_debugreg(current->thread.debugreg2, 2);
+ set_debugreg(current->thread.debugreg3, 3);
/* no 4 and 5 */
- set_debugreg(current->thread.debugreg[6], 6);
- set_debugreg(current->thread.debugreg[7], 7);
+ set_debugreg(current->thread.debugreg6, 6);
+ set_debugreg(current->thread.debugreg7, 7);
}

}
diff --git a/include/asm-x86/processor_32.h b/include/asm-x86/processor_32.h
index c85400f..d50a4b4 100644
--- a/include/asm-x86/processor_32.h
+++ b/include/asm-x86/processor_32.h
@@ -353,7 +353,12 @@ struct thread_struct {
unsigned long fs;
unsigned long gs;
/* Hardware debugging registers */
- unsigned long debugreg[8]; /* %%db0-7 debug registers */
+ unsigned long debugreg0;
+ unsigned long debugreg1;
+ unsigned long debugreg2;
+ unsigned long debugreg3;
+ unsigned long debugreg6;
+ unsigned long debugreg7;
/* fault info */
unsigned long cr2, trap_no, error_code;
/* floating point info */