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

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

arch/powerpc/include/asm/irq.h

+5 −5
Original line number Diff line number Diff line
@@ -48,16 +48,16 @@ struct pt_regs; 
 * Per-cpu stacks for handling critical, debug and machine check

 * level interrupts.

 */

extern struct thread_info *critirq_ctx[NR_CPUS];

extern struct thread_info *dbgirq_ctx[NR_CPUS];

extern struct thread_info *mcheckirq_ctx[NR_CPUS];

extern void *critirq_ctx[NR_CPUS];

extern void *dbgirq_ctx[NR_CPUS];

extern void *mcheckirq_ctx[NR_CPUS];

#endif



/*

 * Per-cpu stacks for handling hard and soft interrupts.

 */

extern struct thread_info *hardirq_ctx[NR_CPUS];

extern struct thread_info *softirq_ctx[NR_CPUS];

extern void *hardirq_ctx[NR_CPUS];

extern void *softirq_ctx[NR_CPUS];



void call_do_softirq(void *sp);

void call_do_irq(struct pt_regs *regs, void *sp);

arch/powerpc/include/asm/processor.h

+1 −2
Original line number Diff line number Diff line
@@ -270,8 +270,7 @@ struct thread_struct { 
#define ARCH_MIN_TASKALIGN 16



#define INIT_SP		(sizeof(init_stack) + (unsigned long) &init_stack)

#define INIT_SP_LIMIT \

	(_ALIGN_UP(sizeof(struct thread_info), 16) + (unsigned long)&init_stack)

#define INIT_SP_LIMIT	((unsigned long)&init_stack)



#ifdef CONFIG_SPE

#define SPEFSCR_INIT \

arch/powerpc/kernel/asm-offsets.c

+0 −1
Original line number Diff line number Diff line
@@ -92,7 +92,6 @@ int main(void) 
	DEFINE(SIGSEGV, SIGSEGV);

	DEFINE(NMI_MASK, NMI_MASK);

#else

	DEFINE(THREAD_INFO_GAP, _ALIGN_UP(sizeof(struct thread_info), 16));

	OFFSET(KSP_LIMIT, thread_struct, ksp_limit);

#ifdef CONFIG_PPC_RTAS

	OFFSET(RTAS_SP, thread_struct, rtas_sp);

arch/powerpc/kernel/entry_32.S

+4 −10
Original line number Diff line number Diff line
@@ -97,14 +97,11 @@ crit_transfer_to_handler: 
	mfspr	r0,SPRN_SRR1

	stw	r0,_SRR1(r11)



	/* set the stack limit to the current stack

	 * and set the limit to protect the thread_info

	 * struct

	 */

	/* set the stack limit to the current stack */

	mfspr	r8,SPRN_SPRG_THREAD

	lwz	r0,KSP_LIMIT(r8)

	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)

	/* fall through */

#endif
@@ -121,14 +118,11 @@ crit_transfer_to_handler: 
	mfspr	r0,SPRN_SRR1

	stw	r0,crit_srr1@l(0)



	/* set the stack limit to the current stack

	 * and set the limit to protect the thread_info

	 * struct

	 */

	/* set the stack limit to the current stack */

	mfspr	r8,SPRN_SPRG_THREAD

	lwz	r0,KSP_LIMIT(r8)

	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)

	/* fall through */

#endif

arch/powerpc/kernel/irq.c

+9 −10
Original line number Diff line number Diff line
@@ -618,9 +618,8 @@ static inline void check_stack_overflow(void) 
	sp = current_stack_pointer() & (THREAD_SIZE-1);



	/* check for stack overflow: is there less than 2KB free? */

	if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {

		pr_err("do_IRQ: stack overflow: %ld\n",

			sp - sizeof(struct thread_info));

	if (unlikely(sp < 2048)) {

		pr_err("do_IRQ: stack overflow: %ld\n", sp);

		dump_stack();

	}

#endif
@@ -660,7 +659,7 @@ void __do_irq(struct pt_regs *regs) 
void do_IRQ(struct pt_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 */

	curtp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
@@ -686,17 +685,17 @@ void __init init_IRQ(void) 
}



#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)

struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;

struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;

struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;

void   *critirq_ctx[NR_CPUS] __read_mostly;

void    *dbgirq_ctx[NR_CPUS] __read_mostly;

void *mcheckirq_ctx[NR_CPUS] __read_mostly;

#endif



struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;

struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;

void *softirq_ctx[NR_CPUS] __read_mostly;

void *hardirq_ctx[NR_CPUS] __read_mostly;



void do_softirq_own_stack(void)

{

	struct thread_info *irqtp;

	void *irqtp;



	irqtp = softirq_ctx[smp_processor_id()];

	call_do_softirq(irqtp);

CRA Git | Maintained and supported by SUSTech CRA and CCSE