On 17/03/07, Paul Brook <[EMAIL PROTECTED]> wrote:
On Friday 16 March 2007 22:06, andrzej zaborowski wrote:
> This patch contains some ugly but very useful chnages:
> - in cpu-exec.c, halt the arm CPU on CPU_INTERRUPT_HALT like in other
> architectures.
This is ok. Though I'd prefer it to actually be common code (like
CPU_INTERRUPT_DEBUG).
> - wake the cpu up on CPU_INTERRUPT_EXITTB - this serves waking the
> CPU up without asserting IRQ or FIQ, which is possible on PXA. Would
> it be better to add a separate interrupt type instead?
I think this is probably ok. Could do with a comment somewhere saying so.
> - in target-arm/translate.c, don't terminate the TB after a CP15
> write. The purpose of this is to imitate the real processor's
> instruction cache (to some degree). OSes should never need rely on the
> cache prefetch but unfortunately Linux for pxa does when it's waking
> up from sleep or deep idle, when enabling the MMU (simplifies things a
> lot for Linux).
This is not acceptable in its current form. IIRC on arm cores the effects take
effect once all insn have worked through the pipeline (typically a few
cycles), and I bet there's code that relies on this. ie:
mcr cp15, ...;nop;nop;nop;nop;@expect cp15 write to have taken effect by now
A more acceptable solution would be:
- Only extend the TB for the specific instruction that linux abuses
- Limit the number of instructions that can follow before the end of the TB.
- Add a comment saying what this hack is for.
Ok. Attaching a second version of this patch. The number of
instructions after MMU enable and before TB ends is limited by the
obligatory CPWAIT rather than in qemu.
Regards,
Andrzej
From 37336004f611f544fc7d2eb763445fdca3109cdf Mon Sep 17 00:00:00 2001
From: Andrzej Zaborowski <[EMAIL PROTECTED]>
Date: Sat, 17 Mar 2007 21:26:12 +0100
Subject: [PATCH] PXA-specific ARM hacks.
---
cpu-all.h | 3 ++-
cpu-exec.c | 20 +++++++++++---------
target-arm/translate.c | 7 ++++++-
3 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/cpu-all.h b/cpu-all.h
index 9b617fc..177bcba 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -763,7 +763,8 @@ void cpu_dump_statistics (CPUState *env, FILE *f,
int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
int flags);
-void cpu_abort(CPUState *env, const char *fmt, ...);
+void cpu_abort(CPUState *env, const char *fmt, ...)
+ __attribute__ ((__format__ (__printf__, 2, 3)));
extern CPUState *first_cpu;
extern CPUState *cpu_single_env;
extern int code_copy_enabled;
diff --git a/cpu-exec.c b/cpu-exec.c
index 48c2a93..10e2f2b 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -275,9 +275,10 @@ int cpu_exec(CPUState *env1)
#elif defined(TARGET_ARM)
if (env1->halted) {
/* An interrupt wakes the CPU even if the I and F CPSR bits are
- set. */
- if (env1->interrupt_request
- & (CPU_INTERRUPT_FIQ | CPU_INTERRUPT_HARD)) {
+ set. We use EXITTB to silently wake CPU without causing an
+ actual interrupt. */
+ if (env1->interrupt_request &
+ (CPU_INTERRUPT_FIQ | CPU_INTERRUPT_HARD | CPU_INTERRUPT_EXITTB)) {
env1->halted = 0;
} else {
return EXCP_HALTED;
@@ -414,6 +415,12 @@ int cpu_exec(CPUState *env1)
env->exception_index = EXCP_DEBUG;
cpu_loop_exit();
}
+ if (interrupt_request & CPU_INTERRUPT_HALT) {
+ env->interrupt_request &= ~CPU_INTERRUPT_HALT;
+ env->halted = 1;
+ env->exception_index = EXCP_HLT;
+ cpu_loop_exit();
+ }
#if defined(TARGET_I386)
if ((interrupt_request & CPU_INTERRUPT_SMI) &&
!(env->hflags & HF_SMM_MASK)) {
@@ -511,12 +518,7 @@ int cpu_exec(CPUState *env1)
} else if (interrupt_request & CPU_INTERRUPT_TIMER) {
//do_interrupt(0, 0, 0, 0, 0);
env->interrupt_request &= ~CPU_INTERRUPT_TIMER;
- } else if (interrupt_request & CPU_INTERRUPT_HALT) {
- env->interrupt_request &= ~CPU_INTERRUPT_HALT;
- env->halted = 1;
- env->exception_index = EXCP_HLT;
- cpu_loop_exit();
- }
+ }
#elif defined(TARGET_ARM)
if (interrupt_request & CPU_INTERRUPT_FIQ
&& !(env->uncached_cpsr & CPSR_F)) {
diff --git a/target-arm/translate.c b/target-arm/translate.c
index cd1c04d..885637c 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -1605,8 +1605,13 @@ static int disas_cp15_insn(DisasContext *s, uint32_t
insn)
} else {
gen_movl_T0_reg(s, rd);
gen_op_movl_cp15_T0(insn);
+ /* Normally we would always end the TB here, but Linux
+ * arch/arm/mach-pxa/sleep.S expects two instructions following
+ * an MMU enable to execute from cache. Imitate this behaviour. */
+ if (!arm_feature(env, ARM_FEATURE_XSCALE) ||
+ (insn & 0x0fff0fff) != 0x0e010f10)
+ gen_lookup_tb(s);
}
- gen_lookup_tb(s);
return 0;
}
--
1.4.4.3
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