Re: [Qemu-devel] [PATCH 1/4] w64: Fix TCG helper functions with 5 arguments

[Aurelien Jarno <aurelien@aurel32.net>]

On Thu, Sep 13, 2012 at 07:37:43PM +0200, Stefan Weil wrote:
> TCG uses 6 registers for function arguments on 64 bit Linux hosts,
> but only 4 registers on W64 hosts.
> 
> Commit 2999a0b20074a7e4a58f56572bb1436749368f59 increased the number
> of arguments for some important helper functions from 4 to 5
> which triggered a bug for W64 hosts: QEMU aborts when executing
> helper_lcall_real in the guest's BIOS because function
> tcg_target_get_call_iarg_regs_count always returned 6.
> 
> As W64 has only 4 registers for arguments, the 5th argument must be
> passed on the stack using a correct stack offset.
> 
> Signed-off-by: Stefan Weil <sw@weilnetz.de>
> ---
>  tcg/i386/tcg-target.c |    2 +-
>  tcg/i386/tcg-target.h |    4 ++++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index da17bba..43b5572 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -118,7 +118,7 @@ static void patch_reloc(uint8_t *code_ptr, int type,
>  static inline int tcg_target_get_call_iarg_regs_count(int flags)
>  {
>      if (TCG_TARGET_REG_BITS == 64) {
> -        return 6;
> +        return ARRAY_SIZE(tcg_target_call_iarg_regs);
>      }
>  
>      return 0;
> diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h
> index c3cfe05..87417d0 100644
> --- a/tcg/i386/tcg-target.h
> +++ b/tcg/i386/tcg-target.h
> @@ -67,7 +67,11 @@ typedef enum {
>  /* used for function call generation */
>  #define TCG_REG_CALL_STACK TCG_REG_ESP 
>  #define TCG_TARGET_STACK_ALIGN 16
> +#if defined(_WIN64)
> +#define TCG_TARGET_CALL_STACK_OFFSET 32
> +#else
>  #define TCG_TARGET_CALL_STACK_OFFSET 0
> +#endif
>  
>  /* optional instructions */
>  #define TCG_TARGET_HAS_div2_i32         1
> -- 
> 1.7.10
> 
> 

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net