Commit a7916a1d authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman

powerpc: regain entire stack space

thread_info is not anymore in the stack, so the entire stack
can now be used.

There is also no risk anymore of corrupting task_cpu(p) with a
stack overflow so the patch removes the test.

When doing this, an explicit test for NULL stack pointer is
needed in validate_sp() as it is not anymore implicitely covered
by the sizeof(thread_info) gap.

In the meantime, with the previous patch all pointers to the stacks
are not anymore pointers to thread_info so this patch changes them
to void*
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent ed1cd6de
...@@ -48,16 +48,16 @@ struct pt_regs; ...@@ -48,16 +48,16 @@ struct pt_regs;
* Per-cpu stacks for handling critical, debug and machine check * Per-cpu stacks for handling critical, debug and machine check
* level interrupts. * level interrupts.
*/ */
extern struct thread_info *critirq_ctx[NR_CPUS]; extern void *critirq_ctx[NR_CPUS];
extern struct thread_info *dbgirq_ctx[NR_CPUS]; extern void *dbgirq_ctx[NR_CPUS];
extern struct thread_info *mcheckirq_ctx[NR_CPUS]; extern void *mcheckirq_ctx[NR_CPUS];
#endif #endif
/* /*
* Per-cpu stacks for handling hard and soft interrupts. * Per-cpu stacks for handling hard and soft interrupts.
*/ */
extern struct thread_info *hardirq_ctx[NR_CPUS]; extern void *hardirq_ctx[NR_CPUS];
extern struct thread_info *softirq_ctx[NR_CPUS]; extern void *softirq_ctx[NR_CPUS];
void call_do_softirq(void *sp); void call_do_softirq(void *sp);
void call_do_irq(struct pt_regs *regs, void *sp); void call_do_irq(struct pt_regs *regs, void *sp);
......
...@@ -270,8 +270,7 @@ struct thread_struct { ...@@ -270,8 +270,7 @@ struct thread_struct {
#define ARCH_MIN_TASKALIGN 16 #define ARCH_MIN_TASKALIGN 16
#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack) #define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
#define INIT_SP_LIMIT \ #define INIT_SP_LIMIT ((unsigned long)&init_stack)
(_ALIGN_UP(sizeof(struct thread_info), 16) + (unsigned long)&init_stack)
#ifdef CONFIG_SPE #ifdef CONFIG_SPE
#define SPEFSCR_INIT \ #define SPEFSCR_INIT \
......
...@@ -92,7 +92,6 @@ int main(void) ...@@ -92,7 +92,6 @@ int main(void)
DEFINE(SIGSEGV, SIGSEGV); DEFINE(SIGSEGV, SIGSEGV);
DEFINE(NMI_MASK, NMI_MASK); DEFINE(NMI_MASK, NMI_MASK);
#else #else
DEFINE(THREAD_INFO_GAP, _ALIGN_UP(sizeof(struct thread_info), 16));
OFFSET(KSP_LIMIT, thread_struct, ksp_limit); OFFSET(KSP_LIMIT, thread_struct, ksp_limit);
#ifdef CONFIG_PPC_RTAS #ifdef CONFIG_PPC_RTAS
OFFSET(RTAS_SP, thread_struct, rtas_sp); OFFSET(RTAS_SP, thread_struct, rtas_sp);
......
...@@ -97,14 +97,11 @@ crit_transfer_to_handler: ...@@ -97,14 +97,11 @@ crit_transfer_to_handler:
mfspr r0,SPRN_SRR1 mfspr r0,SPRN_SRR1
stw r0,_SRR1(r11) stw r0,_SRR1(r11)
/* set the stack limit to the current stack /* set the stack limit to the current stack */
* and set the limit to protect the thread_info
* struct
*/
mfspr r8,SPRN_SPRG_THREAD mfspr r8,SPRN_SPRG_THREAD
lwz r0,KSP_LIMIT(r8) lwz r0,KSP_LIMIT(r8)
stw r0,SAVED_KSP_LIMIT(r11) stw r0,SAVED_KSP_LIMIT(r11)
rlwimi r0,r1,0,0,(31-THREAD_SHIFT) rlwinm r0,r1,0,0,(31 - THREAD_SHIFT)
stw r0,KSP_LIMIT(r8) stw r0,KSP_LIMIT(r8)
/* fall through */ /* fall through */
#endif #endif
...@@ -121,14 +118,11 @@ crit_transfer_to_handler: ...@@ -121,14 +118,11 @@ crit_transfer_to_handler:
mfspr r0,SPRN_SRR1 mfspr r0,SPRN_SRR1
stw r0,crit_srr1@l(0) stw r0,crit_srr1@l(0)
/* set the stack limit to the current stack /* set the stack limit to the current stack */
* and set the limit to protect the thread_info
* struct
*/
mfspr r8,SPRN_SPRG_THREAD mfspr r8,SPRN_SPRG_THREAD
lwz r0,KSP_LIMIT(r8) lwz r0,KSP_LIMIT(r8)
stw r0,saved_ksp_limit@l(0) stw r0,saved_ksp_limit@l(0)
rlwimi r0,r1,0,0,(31-THREAD_SHIFT) rlwinm r0,r1,0,0,(31 - THREAD_SHIFT)
stw r0,KSP_LIMIT(r8) stw r0,KSP_LIMIT(r8)
/* fall through */ /* fall through */
#endif #endif
......
...@@ -618,9 +618,8 @@ static inline void check_stack_overflow(void) ...@@ -618,9 +618,8 @@ static inline void check_stack_overflow(void)
sp = current_stack_pointer() & (THREAD_SIZE-1); sp = current_stack_pointer() & (THREAD_SIZE-1);
/* check for stack overflow: is there less than 2KB free? */ /* check for stack overflow: is there less than 2KB free? */
if (unlikely(sp < (sizeof(struct thread_info) + 2048))) { if (unlikely(sp < 2048)) {
pr_err("do_IRQ: stack overflow: %ld\n", pr_err("do_IRQ: stack overflow: %ld\n", sp);
sp - sizeof(struct thread_info));
dump_stack(); dump_stack();
} }
#endif #endif
...@@ -660,7 +659,7 @@ void __do_irq(struct pt_regs *regs) ...@@ -660,7 +659,7 @@ void __do_irq(struct pt_regs *regs)
void do_IRQ(struct pt_regs *regs) void do_IRQ(struct pt_regs *regs)
{ {
struct pt_regs *old_regs = set_irq_regs(regs); struct pt_regs *old_regs = set_irq_regs(regs);
struct thread_info *curtp, *irqtp, *sirqtp; void *curtp, *irqtp, *sirqtp;
/* Switch to the irq stack to handle this */ /* Switch to the irq stack to handle this */
curtp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1)); curtp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
...@@ -686,17 +685,17 @@ void __init init_IRQ(void) ...@@ -686,17 +685,17 @@ void __init init_IRQ(void)
} }
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x) #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
struct thread_info *critirq_ctx[NR_CPUS] __read_mostly; void *critirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *dbgirq_ctx[NR_CPUS] __read_mostly; void *dbgirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly; void *mcheckirq_ctx[NR_CPUS] __read_mostly;
#endif #endif
struct thread_info *softirq_ctx[NR_CPUS] __read_mostly; void *softirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly; void *hardirq_ctx[NR_CPUS] __read_mostly;
void do_softirq_own_stack(void) void do_softirq_own_stack(void)
{ {
struct thread_info *irqtp; void *irqtp;
irqtp = softirq_ctx[smp_processor_id()]; irqtp = softirq_ctx[smp_processor_id()];
call_do_softirq(irqtp); call_do_softirq(irqtp);
......
...@@ -46,11 +46,10 @@ _GLOBAL(call_do_softirq) ...@@ -46,11 +46,10 @@ _GLOBAL(call_do_softirq)
mflr r0 mflr r0
stw r0,4(r1) stw r0,4(r1)
lwz r10,THREAD+KSP_LIMIT(r2) lwz r10,THREAD+KSP_LIMIT(r2)
addi r11,r3,THREAD_INFO_GAP stw r3, THREAD+KSP_LIMIT(r2)
stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3) stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3)
mr r1,r3 mr r1,r3
stw r10,8(r1) stw r10,8(r1)
stw r11,THREAD+KSP_LIMIT(r2)
bl __do_softirq bl __do_softirq
lwz r10,8(r1) lwz r10,8(r1)
lwz r1,0(r1) lwz r1,0(r1)
...@@ -66,11 +65,10 @@ _GLOBAL(call_do_irq) ...@@ -66,11 +65,10 @@ _GLOBAL(call_do_irq)
mflr r0 mflr r0
stw r0,4(r1) stw r0,4(r1)
lwz r10,THREAD+KSP_LIMIT(r2) lwz r10,THREAD+KSP_LIMIT(r2)
addi r11,r4,THREAD_INFO_GAP stw r4, THREAD+KSP_LIMIT(r2)
stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4) stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4)
mr r1,r4 mr r1,r4
stw r10,8(r1) stw r10,8(r1)
stw r11,THREAD+KSP_LIMIT(r2)
bl __do_irq bl __do_irq
lwz r10,8(r1) lwz r10,8(r1)
lwz r1,0(r1) lwz r1,0(r1)
......
...@@ -1691,8 +1691,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, ...@@ -1691,8 +1691,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
sp -= STACK_FRAME_OVERHEAD; sp -= STACK_FRAME_OVERHEAD;
p->thread.ksp = sp; p->thread.ksp = sp;
#ifdef CONFIG_PPC32 #ifdef CONFIG_PPC32
p->thread.ksp_limit = (unsigned long)task_stack_page(p) + p->thread.ksp_limit = (unsigned long)end_of_stack(p);
_ALIGN_UP(sizeof(struct thread_info), 16);
#endif #endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT #ifdef CONFIG_HAVE_HW_BREAKPOINT
p->thread.ptrace_bps[0] = NULL; p->thread.ptrace_bps[0] = NULL;
...@@ -1995,21 +1994,14 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, ...@@ -1995,21 +1994,14 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
unsigned long stack_page; unsigned long stack_page;
unsigned long cpu = task_cpu(p); unsigned long cpu = task_cpu(p);
/* stack_page = (unsigned long)hardirq_ctx[cpu];
* Avoid crashing if the stack has overflowed and corrupted if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
* task_cpu(p), which is in the thread_info struct.
*/
if (cpu < NR_CPUS && cpu_possible(cpu)) {
stack_page = (unsigned long) hardirq_ctx[cpu];
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1; return 1;
stack_page = (unsigned long) softirq_ctx[cpu]; stack_page = (unsigned long)softirq_ctx[cpu];
if (sp >= stack_page + sizeof(struct thread_struct) if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1; return 1;
}
return 0; return 0;
} }
...@@ -2018,8 +2010,10 @@ int validate_sp(unsigned long sp, struct task_struct *p, ...@@ -2018,8 +2010,10 @@ int validate_sp(unsigned long sp, struct task_struct *p,
{ {
unsigned long stack_page = (unsigned long)task_stack_page(p); unsigned long stack_page = (unsigned long)task_stack_page(p);
if (sp >= stack_page + sizeof(struct thread_struct) if (sp < THREAD_SIZE)
&& sp <= stack_page + THREAD_SIZE - nbytes) return 0;
if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes)
return 1; return 1;
return valid_irq_stack(sp, p, nbytes); return valid_irq_stack(sp, p, nbytes);
......
...@@ -716,19 +716,19 @@ void __init emergency_stack_init(void) ...@@ -716,19 +716,19 @@ void __init emergency_stack_init(void)
limit = min(ppc64_bolted_size(), ppc64_rma_size); limit = min(ppc64_bolted_size(), ppc64_rma_size);
for_each_possible_cpu(i) { for_each_possible_cpu(i) {
struct thread_info *ti; void *ti;
ti = alloc_stack(limit, i); ti = alloc_stack(limit, i);
paca_ptrs[i]->emergency_sp = (void *)ti + THREAD_SIZE; paca_ptrs[i]->emergency_sp = ti + THREAD_SIZE;
#ifdef CONFIG_PPC_BOOK3S_64 #ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for NMI exception handling. */ /* emergency stack for NMI exception handling. */
ti = alloc_stack(limit, i); ti = alloc_stack(limit, i);
paca_ptrs[i]->nmi_emergency_sp = (void *)ti + THREAD_SIZE; paca_ptrs[i]->nmi_emergency_sp = ti + THREAD_SIZE;
/* emergency stack for machine check exception handling. */ /* emergency stack for machine check exception handling. */
ti = alloc_stack(limit, i); ti = alloc_stack(limit, i);
paca_ptrs[i]->mc_emergency_sp = (void *)ti + THREAD_SIZE; paca_ptrs[i]->mc_emergency_sp = ti + THREAD_SIZE;
#endif #endif
} }
} }
......
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