target/loongarch: Fix the CSRRD CPUID instruction on big endian hosts

The test in tests/avocado/machine_loongarch.py is currently failing
on big endian hosts like s390x. By comparing the traces between running
the QEMU_EFI.fd bios on a s390x and on a x86 host, it's quickly obvious
that the CSRRD instruction for the CPUID is behaving differently. And
indeed: The code currently does a long read (i.e. 64 bit) from the
address that points to the CPUState->cpu_index field (with tcg_gen_ld_tl()
in the trans_csrrd() function). But this cpu_index field is only an "int"
(i.e. 32 bit). While this dirty pointer magic works on little endian hosts,
it of course fails on big endian hosts. Fix it by using a proper helper
function instead.

Message-Id: <20230720175307.854460-1-thuth@redhat.com>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit c34ad459926f6c600a55fe6782a27edfa405d60b)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index e15c633b0bf9182e3e6613df460eb33c42a8fd21..6fc583f3e89151fc8c61670eff951519a28fd05e 100644 (file)
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -317,6 +317,7 @@ typedef struct CPUArchState {
     uint64_t CSR_DBG;
     uint64_t CSR_DERA;
     uint64_t CSR_DSAVE;
+    uint64_t CSR_CPUID;
 
 #ifndef CONFIG_USER_ONLY
     LoongArchTLB  tlb[LOONGARCH_TLB_MAX];

diff --git a/target/loongarch/csr_helper.c b/target/loongarch/csr_helper.c
index 7e027878957fde08bbbd6420379c503a37e1a581..b778e6952d56e65f4172008fa82fec8cfece969d 100644 (file)
--- a/target/loongarch/csr_helper.c
+++ b/target/loongarch/csr_helper.c
@@ -36,6 +36,15 @@ target_ulong helper_csrrd_pgd(CPULoongArchState *env)
     return v;
 }
 
+target_ulong helper_csrrd_cpuid(CPULoongArchState *env)
+{
+    LoongArchCPU *lac = env_archcpu(env);
+
+    env->CSR_CPUID = CPU(lac)->cpu_index;
+
+    return env->CSR_CPUID;
+}
+
 target_ulong helper_csrrd_tval(CPULoongArchState *env)
 {
     LoongArchCPU *cpu = env_archcpu(env);

diff --git a/target/loongarch/helper.h b/target/loongarch/helper.h
index 9c01823a26bb6e8e1fab6600c8b3c20a1bdfb741..f47b0f2d057532c5b80d02cb9849d865c3e1194e 100644 (file)
--- a/target/loongarch/helper.h
+++ b/target/loongarch/helper.h
@@ -98,6 +98,7 @@ DEF_HELPER_1(rdtime_d, i64, env)
 #ifndef CONFIG_USER_ONLY
 /* CSRs helper */
 DEF_HELPER_1(csrrd_pgd, i64, env)
+DEF_HELPER_1(csrrd_cpuid, i64, env)
 DEF_HELPER_1(csrrd_tval, i64, env)
 DEF_HELPER_2(csrwr_estat, i64, env, tl)
 DEF_HELPER_2(csrwr_asid, i64, env, tl)

diff --git a/target/loongarch/insn_trans/trans_privileged.c.inc b/target/loongarch/insn_trans/trans_privileged.c.inc
index 40f82becb04c8b88fe15c772e6be58c352878f3c..e3d92c7a22844f73ef8c74fba8e2cebc89a56dc2 100644 (file)
--- a/target/loongarch/insn_trans/trans_privileged.c.inc
+++ b/target/loongarch/insn_trans/trans_privileged.c.inc
@@ -99,13 +99,7 @@ static const CSRInfo csr_info[] = {
     CSR_OFF(PWCH),
     CSR_OFF(STLBPS),
     CSR_OFF(RVACFG),
-    [LOONGARCH_CSR_CPUID] = {
-        .offset = (int)offsetof(CPUState, cpu_index)
-                  - (int)offsetof(LoongArchCPU, env),
-        .flags = CSRFL_READONLY,
-        .readfn = NULL,
-        .writefn = NULL
-    },
+    CSR_OFF_FUNCS(CPUID, CSRFL_READONLY, gen_helper_csrrd_cpuid, NULL),
     CSR_OFF_FLAGS(PRCFG1, CSRFL_READONLY),
     CSR_OFF_FLAGS(PRCFG2, CSRFL_READONLY),
     CSR_OFF_FLAGS(PRCFG3, CSRFL_READONLY),