Re: [PATCH v4 1/6] target/ppc: Fix instruction loading endianness in alignment interrupt

[Anushree Mathur]

On 5/30/23 18:55, Nicholas Piggin wrote:

> powerpc ifetch endianness depends on MSR[LE] so it has to byteswap
> after cpu_ldl_code(). This corrects DSISR bits in alignment
> interrupts when running in little endian mode.
>
> Reviewed-by: Fabiano Rosas <farosas@suse.de>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  target/ppc/excp_helper.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index c13f2afa04..0274617b4a 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -133,6 +133,26 @@ static void dump_hcall(CPUPPCState *env)
>                    env->nip);
>  }
>  
> +#ifdef CONFIG_TCG
> +/* Return true iff byteswap is needed in a scalar memop */
> +static inline bool need_byteswap(CPUArchState *env)
> +{
> +    /* SOFTMMU builds TARGET_BIG_ENDIAN. Need to swap when MSR[LE] is set */
> +    return !!(env->msr & ((target_ulong)1 << MSR_LE));
> +}
> +
> +static uint32_t ppc_ldl_code(CPUArchState *env, abi_ptr addr)
>     
This hunk fails to compile with configure --disable-tcg
> FAILED: libqemu-ppc64-softmmu.fa.p/target_ppc_excp_helper.c.o
> cc -m64 -mlittle-endian -Ilibqemu-ppc64-softmmu.fa.p -I. -I.. 
> -Itarget/ppc -I../target/ppc -I../dtc/libfdt -Iqapi -Itrace -Iui 
> -Iui/shader -I/usr/include/pixman-1 -I/usr/include/glib-2.0 
> -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 
> -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g 
> -fstack-protector-strong -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wundef 
> -Wwrite-strings -Wmissing-prototypes -Wstrict-prototypes 
> -Wredundant-decls -Wold-style-declaration -Wold-style-definition 
> -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self 
> -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels 
> -Wexpansion-to-defined -Wimplicit-fallthrough=2 
> -Wmissing-format-attribute -Wno-missing-include-dirs 
> -Wno-shift-negative-value -Wno-psabi -isystem 
> /home/Shreya/qemu/linux-headers -isystem linux-headers -iquote . -iquote 
> /home/Shreya/qemu -iquote /home/Shreya/qemu/include -pthread 
> -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE 
> -fno-strict-aliasing -fno-common -fwrapv -fPIE -isystem../linux-headers 
> -isystemlinux-headers -DNEED_CPU_H 
> '-DCONFIG_TARGET="ppc64-softmmu-config-target.h"' 
> '-DCONFIG_DEVICES="ppc64-softmmu-config-devices.h"' -MD -MQ 
> libqemu-ppc64-softmmu.fa.p/target_ppc_excp_helper.c.o -MF 
> libqemu-ppc64-softmmu.fa.p/target_ppc_excp_helper.c.o.d -o 
> libqemu-ppc64-softmmu.fa.p/target_ppc_excp_helper.c.o -c 
> ../target/ppc/excp_helper.c
> ../target/ppc/excp_helper.c:143:49: error: unknown type name ‘abi_ptr’; 
> did you mean ‘si_ptr’?
>    143 | static uint32_t ppc_ldl_code(CPUArchState *env, abi_ptr addr)
>        |                                                 ^~~~~~~
>        |                                                 si_ptr
> ../target/ppc/excp_helper.c: In function ‘powerpc_excp_books’:
> ../target/ppc/excp_helper.c:1416:16: error: implicit declaration of 
> function ‘ppc_ldl_code’ [-Werror=implicit-function-declaration]
>   1416 |         insn = ppc_ldl_code(env, env->nip);
>        |                ^~~~~~~~~~~~
> ../target/ppc/excp_helper.c:1416:16: error: nested extern declaration of 
> ‘ppc_ldl_code’ [-Werror=nested-externs]
> cc1: all warnings being treated as errors
>

> +{
> +    uint32_t insn = cpu_ldl_code(env, addr);
> +
> +    if (need_byteswap(env)) {
> +        insn = bswap32(insn);
> +    }
> +
> +    return insn;
> +}
> +#endif
> +
>  static void ppc_excp_debug_sw_tlb(CPUPPCState *env, int excp)
>  {
>      const char *es;
> @@ -3100,7 +3120,7 @@ void ppc_cpu_do_unaligned_access(CPUState *cs, vaddr vaddr,
>  
>      /* Restore state and reload the insn we executed, for filling in DSISR.  */
>      cpu_restore_state(cs, retaddr);
> -    insn = cpu_ldl_code(env, env->nip);
> +    insn = ppc_ldl_code(env, env->nip);
>  
>      switch (env->mmu_model) {
>      case POWERPC_MMU_SOFT_4xx:
>