The first word of page1 is data, so the whole thing
can't be implemented with emulation of addresses.
Use init_guest_commpage for the allocation.
Hijack trap number 16 to implement cmpxchg.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
linux-user/elfload.c | 50 ++++++++++++++++++++++++++++++++++++-
linux-user/nios2/cpu_loop.c | 50 ++++++++++++++++++++-----------------
target/nios2/translate.c | 9 -------
3 files changed, 76 insertions(+), 33 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index d34cd4fe43..329b2375ef 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1099,6 +1099,47 @@ static void init_thread(struct target_pt_regs *regs,
struct image_info *infop)
regs->estatus = 0x3;
}
+#define LO_COMMPAGE TARGET_PAGE_SIZE
+
+static bool init_guest_commpage(void)
+{
+ static const uint8_t kuser_page[4 + 2 * 64] = {
+ /* __kuser_helper_version */
+ [0x00] = 0x02, 0x00, 0x00, 0x00,
+
+ /* __kuser_cmpxchg */
+ [0x04] = 0x3a, 0x6c, 0x3b, 0x00, /* trap 16 */
+ 0x3a, 0x28, 0x00, 0xf8, /* ret */
+
+ /* __kuser_sigtramp */
+ [0x44] = 0xc4, 0x22, 0x80, 0x00, /* movi r2, __NR_rt_sigreturn */
+ 0x3a, 0x68, 0x3b, 0x00, /* trap 0 */
+ };
+
+ void *want = g2h_untagged(LO_COMMPAGE & -qemu_host_page_size);
+ void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+
+ if (addr == MAP_FAILED) {
+ perror("Allocating guest commpage");
+ exit(EXIT_FAILURE);
+ }
+ if (addr != want) {
+ return false;
+ }
+
+ memcpy(addr, kuser_page, sizeof(kuser_page));
+
+ if (mprotect(addr, qemu_host_page_size, PROT_READ)) {
+ perror("Protecting guest commpage");
+ exit(EXIT_FAILURE);
+ }
+
+ page_set_flags(LO_COMMPAGE, LO_COMMPAGE + TARGET_PAGE_SIZE,
+ PAGE_READ | PAGE_EXEC | PAGE_VALID);
+ return true;
+}
+
#define ELF_EXEC_PAGESIZE 4096
#define USE_ELF_CORE_DUMP
@@ -2160,8 +2201,13 @@ static abi_ulong create_elf_tables(abi_ulong p, int
argc, int envc,
return sp;
}
-#ifndef HI_COMMPAGE
+#if defined(HI_COMMPAGE)
+#define LO_COMMPAGE 0
+#elif defined(LO_COMMPAGE)
#define HI_COMMPAGE 0
+#else
+#define HI_COMMPAGE 0
+#define LO_COMMPAGE 0
#define init_guest_commpage() true
#endif
@@ -2374,6 +2420,8 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
} else {
offset = -(HI_COMMPAGE & -align);
}
+ } else if (LO_COMMPAGE) {
+ loaddr = MIN(loaddr, LO_COMMPAGE & -align);
}
addr = pgb_find_hole(loaddr, hiaddr - loaddr, align, offset);
diff --git a/linux-user/nios2/cpu_loop.c b/linux-user/nios2/cpu_loop.c
index 5c3d01d22d..de0fc63e21 100644
--- a/linux-user/nios2/cpu_loop.c
+++ b/linux-user/nios2/cpu_loop.c
@@ -76,6 +76,32 @@ void cpu_loop(CPUNios2State *env)
force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP,
env->regs[R_PC]);
break;
+
+ case 16: /* 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;
@@ -86,29 +112,7 @@ 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] == 0) {
- put_user_u32(env->regs[6], env->regs[4]);
- }
- end_exclusive();
- env->regs[R_PC] = env->regs[R_RA];
- break;
- /*case 0x1040:*/ /* TODO:__kuser_sigtramp */
- default:
- ;
-kuser_fail:
+ {
info.si_signo = TARGET_SIGSEGV;
info.si_errno = 0;
/* TODO: check env->error_code */
diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index a759877519..f9abc2fdd2 100644
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -795,15 +795,6 @@ static void nios2_tr_translate_insn(DisasContextBase
*dcbase, CPUState *cs)
dc->base.pc_next = pc + 4;
/* Decode an instruction */
-
-#if defined(CONFIG_USER_ONLY)
- /* FIXME: Is this needed ? */
- if (pc >= 0x1000 && pc < 0x2000) {
- t_gen_helper_raise_exception(dc, 0xaa);
- return;
- }
-#endif
-
code = cpu_ldl_code(env, pc);
op = get_opcode(code);
