| Message ID | 1461323527-20148-1-git-send-email-lvivier@redhat.com |
|---|---|
| State | Accepted |
| Headers | show |
On 22.04.2016 13:12, Laurent Vivier wrote: > As the TOC pointer can be corrupted by the main program, > we must restore it in the exception handler. > > As we know where we are loaded, we can now compute it easily. > > To compute it only in the common part of the exception handler > (call_handler), store the address of call_handler at an absolute > address in memory to be able to call the handler from the exception > table (as SLOF does). > > Reported-by: Thomas Huth <thuth@redhat.com> > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > --- > v2: don't add SPAPR_KERNEL_LOAD_ADDR to r2 as > the TOC has been relocated and have directly the good > value. The problem has been reported by Thomas. This seems to fix the issue with the emulator invalid-instruction test. Thanks! Thomas > powerpc/cstart64.S | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S > index c47b67d..2d66032 100644 > --- a/powerpc/cstart64.S > +++ b/powerpc/cstart64.S > @@ -13,6 +13,8 @@ > > #include "spapr.h" > > +#define P_HANDLER 0x2ff8 > + > .section .init > > /* > @@ -46,6 +48,11 @@ start: > add r4, r4, r31 > bl relocate > > + /* compute address of call_handler */ > + > + LOAD_REG_ADDR(r4, call_handler) > + std r4, P_HANDLER(0) > + > /* relocate vector table to base address 0x0 (MSR_IP = 0) */ > > /* source: r4, dest end: r5, destination: r6 */ > @@ -166,6 +173,11 @@ call_handler: > mfsrr1 r0 > std r0, _MSR(r1) > > + /* restore TOC pointer */ > + > + LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR) > + ld r2, (p_toc - start)(r31) > + > /* FIXME: build stack frame */ > > /* call generic handler */ > @@ -221,7 +233,7 @@ call_handler: > mfctr r0 > std r0,_CTR(r1) > > - LOAD_REG_ADDR(r0, call_handler) > + ld r0, P_HANDLER(0) > mtctr r0 > > li r0,\vec > @@ -245,3 +257,5 @@ VECTOR(0x900) > .align 7 > .globl __end_interrupts > __end_interrupts: > + .org P_HANDLER > + .llong 0 > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S index c47b67d..2d66032 100644 --- a/powerpc/cstart64.S +++ b/powerpc/cstart64.S @@ -13,6 +13,8 @@ #include "spapr.h" +#define P_HANDLER 0x2ff8 + .section .init /* @@ -46,6 +48,11 @@ start: add r4, r4, r31 bl relocate + /* compute address of call_handler */ + + LOAD_REG_ADDR(r4, call_handler) + std r4, P_HANDLER(0) + /* relocate vector table to base address 0x0 (MSR_IP = 0) */ /* source: r4, dest end: r5, destination: r6 */ @@ -166,6 +173,11 @@ call_handler: mfsrr1 r0 std r0, _MSR(r1) + /* restore TOC pointer */ + + LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR) + ld r2, (p_toc - start)(r31) + /* FIXME: build stack frame */ /* call generic handler */ @@ -221,7 +233,7 @@ call_handler: mfctr r0 std r0,_CTR(r1) - LOAD_REG_ADDR(r0, call_handler) + ld r0, P_HANDLER(0) mtctr r0 li r0,\vec @@ -245,3 +257,5 @@ VECTOR(0x900) .align 7 .globl __end_interrupts __end_interrupts: + .org P_HANDLER + .llong 0
As the TOC pointer can be corrupted by the main program, we must restore it in the exception handler. As we know where we are loaded, we can now compute it easily. To compute it only in the common part of the exception handler (call_handler), store the address of call_handler at an absolute address in memory to be able to call the handler from the exception table (as SLOF does). Reported-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Laurent Vivier <lvivier@redhat.com> --- v2: don't add SPAPR_KERNEL_LOAD_ADDR to r2 as the TOC has been relocated and have directly the good value. The problem has been reported by Thomas. powerpc/cstart64.S | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)