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>
---
Since v2: no change.

 target/ppc/excp_helper.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 199328f4b6..bc2be4a726 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -133,6 +133,24 @@ static void dump_hcall(CPUPPCState *env)
                   env->nip);
 }
 
+/* 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)
+{
+    uint32_t insn = cpu_ldl_code(env, addr);
+
+    if (need_byteswap(env)) {
+        insn = bswap32(insn);
+    }
+
+    return insn;
+}
+
 static void ppc_excp_debug_sw_tlb(CPUPPCState *env, int excp)
 {
     const char *es;
@@ -3097,7 +3115,7 @@ 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:
-- 
2.40.1

Either this patch or patch 6 broke a gitlab KVM builder (cross-ppc64el-kvm-only)
as follows:


[1441/2019] Compiling C object libqemu-ppc-softmmu.fa.p/target_ppc_excp_helper.c.o
FAILED: libqemu-ppc-softmmu.fa.p/target_ppc_excp_helper.c.o
powerpc64le-linux-gnu-gcc -m64 -mlittle-endian -Ilibqemu-ppc-softmmu.fa.p -I. -I.. -Itarget/ppc -I../target/ppc -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/pixman-1 -I/usr/include/capstone -I/usr/include/spice-server -I/usr/include/spice-1 -I/usr/include/glib-2.0 -I/usr/lib/powerpc64le-linux-gnu/glib-2.0/include -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem /builds/danielhb/qemu/linux-headers -isystem linux-headers -iquote . -iquote /builds/danielhb/qemu -iquote /builds/danielhb/qemu/include -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing -fno-common -fwrapv -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 -fstack-protector-strong -fPIE -isystem../linux-headers -isystemlinux-headers -DNEED_CPU_H '-DCONFIG_TARGET="ppc-softmmu-config-target.h"' '-DCONFIG_DEVICES="ppc-softmmu-config-devices.h"' -MD -MQ libqemu-ppc-softmmu.fa.p/target_ppc_excp_helper.c.o -MF libqemu-ppc-softmmu.fa.p/target_ppc_excp_helper.c.o.d -o libqemu-ppc-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
[1442/2019] Compiling C object libqemu-ppc-softmmu.fa.p/target_ppc_cpu-models.c.o
ninja: build stopped: subcommand failed.
make: *** [Makefile:165: run-ninja] Error 1


More details here:

https://gitlab.com/danielhb/qemu/-/jobs/4293326431


I suppose we're missing an ifdef somewhere to gate this code from KVM code. 'abi_ptr'
is a TCG pointer afaik.



Thanks,

Daniel


On 5/15/23 06:26, 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>
> ---
> Since v2: no change.
> 
>   target/ppc/excp_helper.c | 20 +++++++++++++++++++-
>   1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index 199328f4b6..bc2be4a726 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -133,6 +133,24 @@ static void dump_hcall(CPUPPCState *env)
>                     env->nip);
>   }
>   
> +/* 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)
> +{
> +    uint32_t insn = cpu_ldl_code(env, addr);
> +
> +    if (need_byteswap(env)) {
> +        insn = bswap32(insn);
> +    }
> +
> +    return insn;
> +}
> +
>   static void ppc_excp_debug_sw_tlb(CPUPPCState *env, int excp)
>   {
>       const char *es;
> @@ -3097,7 +3115,7 @@ 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: