On Tue, 2015-02-10 at 20:15 +0800, Jeremy Kerr wrote: > Currently, a 64-bit little-endian zImage.epapr won't boot in epapr mode, > as as we never return from platform_init. > > Before entering C, we initialise our stack by setting r1 16 bytes below > the end of the _bss_stack: > > stwu r0,-16(r1) /* establish a stack frame */ > > However, the called function will save the caller's lr in the caller's > frame's lr save area, at -16(r1) to -32(r1). > > This means that writes to the fdt variable corrupt the saved link > register: > > 0000000020c06018 l O .bss 0000000000001000 _bss_stack > 0000000020c07018 l O .bss 0000000000000008 fdt > > This change allocates the minimum of 32 bytes for the base of the stack > instead.
Is that sufficient for ABI v1 ? It feels like it's broken for BE as well... Ben. > Signed-off-by: Jeremy Kerr <j...@ozlabs.org> > > --- > arch/powerpc/boot/crt0.S | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S > index 14de4f8..bf8eeee 100644 > --- a/arch/powerpc/boot/crt0.S > +++ b/arch/powerpc/boot/crt0.S > @@ -218,7 +218,7 @@ p_base: mflr r10 /* r10 now points to > runtime addr of p_base */ > beq 6f > ld r1,0(r8) > li r0,0 > - stdu r0,-16(r1) /* establish a stack frame */ > + stdu r0,-32(r1) /* establish a stack frame */ > 6: > #endif /* __powerpc64__ */ > /* Call platform_init() */ > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
