powerpc/32: Fix critical and debug interrupts on BOOKE

32 bits BOOKE have special interrupts for debug and other
critical events.

When handling those interrupts, dedicated registers are saved
in the stack frame in addition to the standard registers, leading
to a shift of the pt_regs struct.

Since commit db297c3b07af ("powerpc/32: Don't save thread.regs on
interrupt entry"), the pt_regs struct is expected to be at the
same place all the time.

Instead of handling a special struct in addition to pt_regs, just
add those special registers to struct pt_regs.

Fixes: db297c3b07af ("powerpc/32: Don't save thread.regs on interrupt entry")
Cc: stable@vger.kernel.org
Reported-by: Radu Rendec <radu.rendec@gmail.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/028d5483b4851b01ea4334d0751e7f260419092b.1625637264.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 3e5d470a6155a7226e456fa7bed81c23cb6a892e..14422e85149461ac3b8a55fae85dce7ce280c6e1 100644 (file)
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -70,6 +70,22 @@ struct pt_regs
                unsigned long __pad[4]; /* Maintain 16 byte interrupt stack alignment */
        };
 #endif
+#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
+       struct { /* Must be a multiple of 16 bytes */
+               unsigned long mas0;
+               unsigned long mas1;
+               unsigned long mas2;
+               unsigned long mas3;
+               unsigned long mas6;
+               unsigned long mas7;
+               unsigned long srr0;
+               unsigned long srr1;
+               unsigned long csrr0;
+               unsigned long csrr1;
+               unsigned long dsrr0;
+               unsigned long dsrr1;
+       };
+#endif
 };
 #endif
 

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index a47eefa09bcb2fb56b65263885bb59647cf9639c..5bee245d832b10f50718fa0e5a9e4fb2a81a7fd0 100644 (file)
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -309,24 +309,21 @@ int main(void)
        STACK_PT_REGS_OFFSET(STACK_REGS_IAMR, iamr);
 #endif
 
-#if defined(CONFIG_PPC32)
-#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
-       DEFINE(EXC_LVL_SIZE, STACK_EXC_LVL_FRAME_SIZE);
-       DEFINE(MAS0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
+#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
+       STACK_PT_REGS_OFFSET(MAS0, mas0);
        /* we overload MMUCR for 44x on MAS0 since they are mutually exclusive */
-       DEFINE(MMUCR, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
-       DEFINE(MAS1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas1));
-       DEFINE(MAS2, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas2));
-       DEFINE(MAS3, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas3));
-       DEFINE(MAS6, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas6));
-       DEFINE(MAS7, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas7));
-       DEFINE(_SRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr0));
-       DEFINE(_SRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr1));
-       DEFINE(_CSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr0));
-       DEFINE(_CSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr1));
-       DEFINE(_DSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr0));
-       DEFINE(_DSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr1));
-#endif
+       STACK_PT_REGS_OFFSET(MMUCR, mas0);
+       STACK_PT_REGS_OFFSET(MAS1, mas1);
+       STACK_PT_REGS_OFFSET(MAS2, mas2);
+       STACK_PT_REGS_OFFSET(MAS3, mas3);
+       STACK_PT_REGS_OFFSET(MAS6, mas6);
+       STACK_PT_REGS_OFFSET(MAS7, mas7);
+       STACK_PT_REGS_OFFSET(_SRR0, srr0);
+       STACK_PT_REGS_OFFSET(_SRR1, srr1);
+       STACK_PT_REGS_OFFSET(_CSRR0, csrr0);
+       STACK_PT_REGS_OFFSET(_CSRR1, csrr1);
+       STACK_PT_REGS_OFFSET(_DSRR0, dsrr0);
+       STACK_PT_REGS_OFFSET(_DSRR1, dsrr1);
 #endif
 
        /* About the CPU features table */

diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 87b806e8eded959e1c235868c86be76645cfbc42..e5503420b6c6da576ec6ce7fa994bb6ffc4c5b87 100644 (file)
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -168,20 +168,18 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 /* only on e500mc */
 #define DBG_STACK_BASE         dbgirq_ctx
 
-#define EXC_LVL_FRAME_OVERHEAD (THREAD_SIZE - INT_FRAME_SIZE - EXC_LVL_SIZE)
-
 #ifdef CONFIG_SMP
 #define BOOKE_LOAD_EXC_LEVEL_STACK(level)              \
        mfspr   r8,SPRN_PIR;                            \
        slwi    r8,r8,2;                                \
        addis   r8,r8,level##_STACK_BASE@ha;            \
        lwz     r8,level##_STACK_BASE@l(r8);            \
-       addi    r8,r8,EXC_LVL_FRAME_OVERHEAD;
+       addi    r8,r8,THREAD_SIZE - INT_FRAME_SIZE;
 #else
 #define BOOKE_LOAD_EXC_LEVEL_STACK(level)              \
        lis     r8,level##_STACK_BASE@ha;               \
        lwz     r8,level##_STACK_BASE@l(r8);            \
-       addi    r8,r8,EXC_LVL_FRAME_OVERHEAD;
+       addi    r8,r8,THREAD_SIZE - INT_FRAME_SIZE;
 #endif
 
 /*
@@ -208,7 +206,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
        mtmsr   r11;                                                    \
        mfspr   r11,SPRN_SPRG_THREAD;   /* if from user, start at top of   */\
        lwz     r11, TASK_STACK - THREAD(r11); /* this thread's kernel stack */\
-       addi    r11,r11,EXC_LVL_FRAME_OVERHEAD; /* allocate stack frame    */\
+       addi    r11,r11,THREAD_SIZE - INT_FRAME_SIZE;   /* allocate stack frame    */\
        beq     1f;                                                          \
        /* COMING FROM USER MODE */                                          \
        stw     r9,_CCR(r11);           /* save CR                         */\
@@ -516,24 +514,5 @@ label:
        bl      kernel_fp_unavailable_exception;                              \
        b       interrupt_return
 
-#else /* __ASSEMBLY__ */
-struct exception_regs {
-       unsigned long mas0;
-       unsigned long mas1;
-       unsigned long mas2;
-       unsigned long mas3;
-       unsigned long mas6;
-       unsigned long mas7;
-       unsigned long srr0;
-       unsigned long srr1;
-       unsigned long csrr0;
-       unsigned long csrr1;
-       unsigned long dsrr0;
-       unsigned long dsrr1;
-};
-
-/* ensure this structure is always sized to a multiple of the stack alignment */
-#define STACK_EXC_LVL_FRAME_SIZE       ALIGN(sizeof (struct exception_regs), 16)
-
 #endif /* __ASSEMBLY__ */
 #endif /* __HEAD_BOOKE_H__ */