[OpenBIOS] [PATCH, RFC] ppc: Turn 32-bit ppc64 into a config option, to be deprecated

[Alexander Graf]

On 14.11.2010, at 02:48, Andreas Färber wrote:

> Having 64-bit support as an option allows users to disable
> and test it before it gets officially removed.
> 
> Fork single-bitness macros EXCEPTION_{PREAMBLE,EPILOGUE}:
> Use assembler macros for things that are constant to avoid
> ; and \, and use preprocessor macros to handle differences.
> Adopt QEMU coding style for new code.
> 
> Functional changes for ppc64:
> * Don't clear MSR in preamble.
> * Just save the minimum number of registers since 64-bit code will
>  save the full registers.
> * Reserve 48 bytes of stack frame space for ppc64, according to
>  64-bit PowerPC ELF ABI supplement 1.9.
> * Use RFI macro.
> 
> Cc: Alexander Graf <agraf at suse.de>
> Signed-off-by: Andreas Färber <andreas.faerber at web.de>
> ---
> arch/ppc/qemu/init.c           |    4 ++
> arch/ppc/qemu/start.S          |   92 +++++++++++++++++++++++++++++++++++++++-
> config/examples/ppc_config.xml |    1 +
> 3 files changed, 96 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/ppc/qemu/init.c b/arch/ppc/qemu/init.c
> index 0b781d9..d17c843 100644
> --- a/arch/ppc/qemu/init.c
> +++ b/arch/ppc/qemu/init.c
> @@ -303,6 +303,7 @@ cpu_g4_init(const struct cpudef *cpu)
>     fword("finish-device");
> }
> 
> +#ifdef CONFIG_PPC_64BITSUPPORT
> /* In order to get 64 bit aware handlers that rescue all our
>    GPRs from getting truncated to 32 bits, we need to patch the
>    existing handlers so they jump to our 64 bit aware ones. */
> @@ -322,6 +323,7 @@ ppc64_patch_handlers(void)
>     asm ( "icbi 0, %0" : : "r"(dsi) );
>     asm ( "icbi 0, %0" : : "r"(isi) );
> }
> +#endif
> 
> static void
> cpu_970_init(const struct cpudef *cpu)
> @@ -341,10 +343,12 @@ cpu_970_init(const struct cpudef *cpu)
> 
>     fword("finish-device");
> 
> +#ifdef CONFIG_PPC_64BITSUPPORT
>     /* The 970 is a PPC64 CPU, so we need to activate
>      * 64bit aware interrupt handlers */
> 
>     ppc64_patch_handlers();
> +#endif
> 
>     /* The 970 also implements the HIOR which we need to set to 0 */
> 
> diff --git a/arch/ppc/qemu/start.S b/arch/ppc/qemu/start.S
> index e86bdfd..6cf20cf 100644
> --- a/arch/ppc/qemu/start.S
> +++ b/arch/ppc/qemu/start.S
> @@ -14,6 +14,7 @@
>  *
>  */
> 
> +#include "autoconf.h"
> #include "asm/asmdefs.h"
> #include "asm/processor.h"
> 
> @@ -24,6 +25,8 @@
> #define ILLEGAL_VECTOR( v )	.org __vectors + v ; vector__##v: bl trap_error ;
> #define VECTOR( v, dummystr )	.org __vectors + v ; vector__##v
> 
> +#ifdef CONFIG_PPC_64BITSUPPORT
> +
> /* We're trying to use the same code for the ppc32 and ppc64 handlers here.
>  * On ppc32 we only save/restore the registers, C considers volatile.
>  *
> @@ -176,6 +179,89 @@
> #undef stl
> #undef ll
> 
> +#else
> +
> +#ifdef __powerpc64__
> +
> +#define ULONG_SIZE 8
> +#define STACKFRAME_MINSIZE 48
> +#define stl std
> +#define ll  ld
> +
> +#else
> +
> +#define ULONG_SIZE 4
> +#define STACKFRAME_MINSIZE 16
> +#define stl stw
> +#define ll  lwz
> +
> +#endif
> +
> +.macro EXCEPTION_PREAMBLE
> +    mtsprg1 r1 /* scratch */
> +    mfsprg0 r1 /* exception stack in sprg0 */
> +    addi    r1, r1, -(20 * ULONG_SIZE) /* push exception frame */
> +
> +    stl     r0,  ( 0 * ULONG_SIZE)(r1) /* save r0 */
> +    mfsprg1 r0
> +    stl     r0,  ( 1 * ULONG_SIZE)(r1) /* save r1 */
> +    stl     r2,  ( 2 * ULONG_SIZE)(r1) /* save r2 */
> +    stl     r3,  ( 3 * ULONG_SIZE)(r1) /* save r3 */
> +    stl     r4,  ( 4 * ULONG_SIZE)(r1)
> +    stl     r5,  ( 5 * ULONG_SIZE)(r1)
> +    stl     r6,  ( 6 * ULONG_SIZE)(r1)
> +    stl     r7,  ( 7 * ULONG_SIZE)(r1)
> +    stl     r8,  ( 8 * ULONG_SIZE)(r1)
> +    stl     r9,  ( 9 * ULONG_SIZE)(r1)
> +    stl     r10, (10 * ULONG_SIZE)(r1)
> +    stl     r11, (11 * ULONG_SIZE)(r1)
> +    stl     r12, (12 * ULONG_SIZE)(r1)
> +
> +    mflr    r0
> +    stl     r0,  (13 * ULONG_SIZE)(r1)
> +    mfcr    r0
> +    stl     r0,  (14 * ULONG_SIZE)(r1)
> +    mfctr   r0
> +    stl     r0,  (15 * ULONG_SIZE)(r1)
> +    mfxer   r0
> +    stl     r0,  (16 * ULONG_SIZE)(r1)
> +
> +    /* 76(r1) unused */
> +
> +    addi r1, r1, -STACKFRAME_MINSIZE /* C ABI saves LR and SP */
> +.endm
> +
> +.macro EXCEPTION_EPILOGUE
> +    addi r1, r1,  STACKFRAME_MINSIZE /* pop ABI frame */
> +
> +    ll    r0,  (13 * ULONG_SIZE)(r1)
> +    mtlr  r0
> +    ll    r0,  (14 * ULONG_SIZE)(r1)
> +    mtcr  r0
> +    ll    r0,  (15 * ULONG_SIZE)(r1)
> +    mtctr r0
> +    ll    r0,  (16 * ULONG_SIZE)(r1)
> +    mtxer r0
> +
> +    ll    r0,  ( 0 * ULONG_SIZE)(r1)
> +    ll    r2,  ( 2 * ULONG_SIZE)(r1)
> +    ll    r3,  ( 3 * ULONG_SIZE)(r1)
> +    ll    r4,  ( 4 * ULONG_SIZE)(r1)
> +    ll    r5,  ( 5 * ULONG_SIZE)(r1)
> +    ll    r6,  ( 6 * ULONG_SIZE)(r1)
> +    ll    r7,  ( 7 * ULONG_SIZE)(r1)
> +    ll    r8,  ( 8 * ULONG_SIZE)(r1)
> +    ll    r9,  ( 9 * ULONG_SIZE)(r1)
> +    ll    r10, (10 * ULONG_SIZE)(r1)
> +    ll    r11, (11 * ULONG_SIZE)(r1)
> +    ll    r12, (12 * ULONG_SIZE)(r1)
> +
> +    ll    r1,  ( 1 * ULONG_SIZE)(r1) /* restore stack at last */
> +    RFI
> +.endm


I don't think this really belongs in this patch, no? :)


Alex