qemu: Update ppc instruction fix to match revised upstream version

Upstream asked for some changes, this updates our patch to match. The differences
likely don't change our real world use.

(From OE-Core rev: 411e3f76840c06580fa8d2e764ae504b8f0ad46b)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 42591e07a469cff881fa087d5251a8c783897634)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 102 insertions, 25 deletions

diff --git a/meta/recipes-devtools/qemu/qemu/ppc.patch b/meta/recipes-devtools/qemu/qemu/ppc.patch
index 395cdb814f..4fce3c81ac 100644
--- a/meta/recipes-devtools/qemu/qemu/ppc.patch
+++ b/meta/recipes-devtools/qemu/qemu/ppc.patch
@@ -1,70 +1,147 @@
-target/ppc: Fix fallback to MFSS for MFFSCRN, MFFSCRNI, MFFSCE and MFFSL
+From d92b63b7d15d4fd202c5802dfe444a96f5d8109c Mon Sep 17 00:00:00 2001
+From: Richard Purdie <richard.purdie@linuxfoundation.org>
+Date: Sat, 6 May 2023 07:42:35 +0100
+Cc: Víctor Colombo <victor.colombo@eldorado.org.br>
+Cc: Matheus Ferst <matheus.ferst@eldorado.org.br>
+Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
+Cc: Richard Henderson <richard.henderson@linaro.org>
+Subject: [PATCH v2] target/ppc: Fix fallback to MFSS for MFFS* instructions on
+ pre 3.0 ISAs
 
-The following commits changed the code such that these instructions became invalid
-on pre 3.0 ISAs:
+The following commits changed the code such that the fallback to MFSS for MFFSCRN,
+MFFSCRNI, MFFSCE and MFFSL on pre 3.0 ISAs was removed and became an illegal instruction:
 
-  bf8adfd88b547680aa857c46098f3a1e94373160 - target/ppc: Move mffscrn[i] to decodetree 
+  bf8adfd88b547680aa857c46098f3a1e94373160 - target/ppc: Move mffscrn[i] to decodetree
   394c2e2fda70da722f20fb60412d6c0ca4bfaa03 - target/ppc: Move mffsce to decodetree
-  3e5bce70efe6bd1f684efbb21fd2a316cbf0657e - target/ppc: Move mffsl to decodetree 
+  3e5bce70efe6bd1f684efbb21fd2a316cbf0657e - target/ppc: Move mffsl to decodetree
 
 The hardware will handle them as a MFFS instruction as the code did previously.
-Restore that behaviour. This means applications that were segfaulting under qemu 
-when encountering these instructions now operate correctly. The instruction
-is used in glibc libm functions for example.
+This means applications that were segfaulting under qemu when encountering these
+instructions which is used in glibc libm functions for example.
 
-Upstream-Status: Submitted [https://lore.kernel.org/qemu-devel/20230504110150.3044402-1-richard.purdie@linuxfoundation.org/]
+The fallback for MFFSCDRN and MFFSCDRNI added in a later patch was also missing.
+
+This patch restores the fallback to MFSS for these instructions on pre 3.0s ISAs
+as the hardware decoder would, fixing the segfaulting libm code. It and also ensures
+the MFSS instruction is used for currently reserved bits to handle other potential
+ISA additions more correctly.
+
+Upstream-Status: Submitted [https://lore.kernel.org/qemu-devel/20230506065240.3177798-1-richard.purdie@linuxfoundation.org/]
 
 Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
+---
+ target/ppc/insn32.decode           | 19 ++++++++++++-------
+ target/ppc/translate/fp-impl.c.inc | 30 ++++++++++++++++++++++++------
+ 2 files changed, 36 insertions(+), 13 deletions(-)
 
-Index: qemu-8.0.0/target/ppc/translate/fp-impl.c.inc
-===================================================================
---- qemu-8.0.0.orig/target/ppc/translate/fp-impl.c.inc
-+++ qemu-8.0.0/target/ppc/translate/fp-impl.c.inc
-@@ -584,7 +584,10 @@ static bool trans_MFFSCE(DisasContext *c
+v2 - switch to use decodetree pattern groups per feedback
+
+diff --git a/target/ppc/insn32.decode b/target/ppc/insn32.decode
+index f8f589e9fd..3c4e2c2fc2 100644
+--- a/target/ppc/insn32.decode
++++ b/target/ppc/insn32.decode
+@@ -390,13 +390,18 @@ SETNBCR         011111 ..... ..... ----- 0111100000 -   @X_bi
+ 
+ ### Move To/From FPSCR
+ 
+-MFFS            111111 ..... 00000 ----- 1001000111 .   @X_t_rc
+-MFFSCE          111111 ..... 00001 ----- 1001000111 -   @X_t
+-MFFSCRN         111111 ..... 10110 ..... 1001000111 -   @X_tb
+-MFFSCDRN        111111 ..... 10100 ..... 1001000111 -   @X_tb
+-MFFSCRNI        111111 ..... 10111 ---.. 1001000111 -   @X_imm2
+-MFFSCDRNI       111111 ..... 10101 --... 1001000111 -   @X_imm3
+-MFFSL           111111 ..... 11000 ----- 1001000111 -   @X_t
++{ 
++  # Before Power ISA v3.0, MFFS bits 11~15 were reserved and should be ignored
++  [
++    MFFSCE          111111 ..... 00001 ----- 1001000111 -   @X_t
++    MFFSCRN         111111 ..... 10110 ..... 1001000111 -   @X_tb
++    MFFSCDRN        111111 ..... 10100 ..... 1001000111 -   @X_tb
++    MFFSCRNI        111111 ..... 10111 ---.. 1001000111 -   @X_imm2
++    MFFSCDRNI       111111 ..... 10101 --... 1001000111 -   @X_imm3
++    MFFSL           111111 ..... 11000 ----- 1001000111 -   @X_t
++  ]
++  MFFS            111111 ..... ----- ----- 1001000111 .   @X_t_rc
++}
+ 
+ ### Decimal Floating-Point Arithmetic Instructions
+ 
+diff --git a/target/ppc/translate/fp-impl.c.inc b/target/ppc/translate/fp-impl.c.inc
+index 57d8437851..10dfd91aa4 100644
+--- a/target/ppc/translate/fp-impl.c.inc
++++ b/target/ppc/translate/fp-impl.c.inc
+@@ -584,7 +584,10 @@ static bool trans_MFFSCE(DisasContext *ctx, arg_X_t *a)
  {
      TCGv_i64 fpscr;
  
 -    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
-+    if (unlikely(!(ctx->insns_flags2 & PPC2_ISA300))) {
-+        return trans_MFFS(ctx, a);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
 +    }
 +
      REQUIRE_FPU(ctx);
  
      gen_reset_fpstatus();
-@@ -597,7 +600,10 @@ static bool trans_MFFSCRN(DisasContext *
+@@ -597,7 +600,10 @@ static bool trans_MFFSCRN(DisasContext *ctx, arg_X_tb *a)
+ {
+     TCGv_i64 t1, fpscr;
+ 
+-    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
++    }
++
+     REQUIRE_FPU(ctx);
+ 
+     t1 = tcg_temp_new_i64();
+@@ -614,7 +620,10 @@ static bool trans_MFFSCDRN(DisasContext *ctx, arg_X_tb *a)
  {
      TCGv_i64 t1, fpscr;
  
 -    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
-+    if (unlikely(!(ctx->insns_flags2 & PPC2_ISA300))) {
-+        return trans_MFFS(ctx, a);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
 +    }
 +
      REQUIRE_FPU(ctx);
  
      t1 = tcg_temp_new_i64();
-@@ -631,7 +637,10 @@ static bool trans_MFFSCRNI(DisasContext
+@@ -631,7 +640,10 @@ static bool trans_MFFSCRNI(DisasContext *ctx, arg_X_imm2 *a)
  {
      TCGv_i64 t1, fpscr;
  
 -    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
-+    if (unlikely(!(ctx->insns_flags2 & PPC2_ISA300))) {
-+        return trans_MFFS(ctx, a);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
 +    }
 +
      REQUIRE_FPU(ctx);
  
      t1 = tcg_temp_new_i64();
-@@ -661,7 +670,10 @@ static bool trans_MFFSCDRNI(DisasContext
+@@ -647,7 +659,10 @@ static bool trans_MFFSCDRNI(DisasContext *ctx, arg_X_imm3 *a)
+ {
+     TCGv_i64 t1, fpscr;
+ 
+-    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
++    }
++
+     REQUIRE_FPU(ctx);
+ 
+     t1 = tcg_temp_new_i64();
+@@ -661,7 +676,10 @@ static bool trans_MFFSCDRNI(DisasContext *ctx, arg_X_imm3 *a)
  {
      TCGv_i64 fpscr;
  
 -    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
-+    if (unlikely(!(ctx->insns_flags2 & PPC2_ISA300))) {
-+        return trans_MFFS(ctx, a);
++    if (!(ctx->insns_flags2 & PPC2_ISA300)) {
++        return false;
 +    }
 +
      REQUIRE_FPU(ctx);
  
      gen_reset_fpstatus();
+-- 
+2.39.2
+