The first word of page1 is data, so the whole thing
can't be implemented with emulation of addresses.
Hijack trap number 31 to implement cmpxchg.
Set default_rt_sigreturn based on the kuser page.
Signed-off-by: Richard Henderson
---
linux-user/nios2/target_signal.h | 3 ++
linux-user/elfload.c | 35 ++
linux-user/nios2/cpu_loop.c | 51 +---
linux-user/nios2/signal.c| 2 +-
target/nios2/translate.c | 9 --
5 files changed, 66 insertions(+), 34 deletions(-)
diff --git a/linux-user/nios2/target_signal.h b/linux-user/nios2/target_signal.h
index aebf749f12..fe266c4c51 100644
--- a/linux-user/nios2/target_signal.h
+++ b/linux-user/nios2/target_signal.h
@@ -19,4 +19,7 @@ typedef struct target_sigaltstack {
#include "../generic/signal.h"
+/* Nios2 uses a fixed address on the kuser page for sigreturn. */
+#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 0
+
#endif /* NIOS2_TARGET_SIGNAL_H */
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 459a26ef1d..7b3a91b3ed 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1100,6 +1100,41 @@ static void elf_core_copy_regs(target_elf_gregset_t
*regs, const CPUMBState *env
static void init_thread(struct target_pt_regs *regs, struct image_info *infop)
{
+static const uint8_t kuser_page[4 + 2 * 64] = {
+/* __kuser_helper_version */
+[0x00] = 0x02, 0x00, 0x00, 0x00,
+
+/* __kuser_cmpxchg */
+[0x04] = 0xfa, 0x6f, 0x3b, 0x00, /* trap 31 */
+ 0x3a, 0x28, 0x00, 0xf8, /* ret */
+
+/* __kuser_sigtramp */
+[0x44] = 0xc4, 0x22, 0x80, 0x00, /* movi r2, __NR_rt_sigreturn */
+ 0x3a, 0x68, 0x3b, 0x00, /* trap 0 */
+};
+
+abi_ulong pg;
+uint8_t *ph;
+
+pg = target_mmap(TARGET_PAGE_SIZE, TARGET_PAGE_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0);
+
+/*
+ * If the mmap doesn't give us exactly page 1, there's nothing
+ * we can do, and it's unlikely that the program will be able
+ * to continue. FIXME: Error out now?
+ */
+assert(pg == TARGET_PAGE_SIZE);
+
+ph = lock_user(VERIFY_WRITE, pg, sizeof(kuser_page), 0);
+memcpy(ph, kuser_page, sizeof(kuser_page));
+unlock_user(ph, pg, sizeof(kuser_page));
+target_mprotect(TARGET_PAGE_SIZE, TARGET_PAGE_SIZE, PROT_READ | PROT_EXEC);
+
+/* Install __kuser_sigtramp */
+default_rt_sigreturn = TARGET_PAGE_SIZE + 0x44;
+
regs->ea = infop->entry;
regs->sp = infop->start_stack;
regs->estatus = 0x3;
diff --git a/linux-user/nios2/cpu_loop.c b/linux-user/nios2/cpu_loop.c
index 246293a501..12070c8a3c 100644
--- a/linux-user/nios2/cpu_loop.c
+++ b/linux-user/nios2/cpu_loop.c
@@ -26,7 +26,6 @@
void cpu_loop(CPUNios2State *env)
{
CPUState *cs = env_cpu(env);
-Nios2CPU *cpu = NIOS2_CPU(cs);
target_siginfo_t info;
int trapnr, ret;
@@ -73,6 +72,32 @@ void cpu_loop(CPUNios2State *env)
force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP,
env->regs[R_PC]);
break;
+
+case 31: /* QEMU specific, for __kuser_cmpxchg */
+{
+abi_ptr g = env->regs[4];
+uint32_t *h, n, o;
+
+if (g & 0x3) {
+force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, g);
+break;
+}
+ret = page_get_flags(g);
+if (!(ret & PAGE_VALID)) {
+force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MAPERR, g);
+break;
+}
+if (!(ret & PAGE_READ) || !(ret & PAGE_WRITE)) {
+force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_ACCERR, g);
+break;
+}
+h = g2h(cs, g);
+o = env->regs[5];
+n = env->regs[6];
+env->regs[2] = qatomic_cmpxchg(h, o, n) - o;
+env->regs[R_PC] += 4;
+}
+break;
}
break;
@@ -83,29 +108,7 @@ void cpu_loop(CPUNios2State *env)
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
case 0xaa:
-switch (env->regs[R_PC]) {
-/*case 0x1000:*/ /* TODO:__kuser_helper_version */
-case 0x1004: /* __kuser_cmpxchg */
-start_exclusive();
-if (env->regs[4] & 0x3) {
-goto kuser_fail;
-}
-ret = get_user_u32(env->regs[2], env->regs[4]);
-if (ret) {
-end_exclusive();
-goto kuser_fail;
-}
-env->regs[2] -= env->regs[5];
-if (env->regs[2]
