Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.12-pull-request' into staging

# gpg: Signature made Tue 13 Mar 2018 17:33:03 GMT
# gpg:                using RSA key F30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-2.12-pull-request:
  linux-user: init_guest_space: Add a comment about search strategy
  linux-user: init_guest_space: Don't try to align if we'll reject it
  linux-user: init_guest_space: Clean up control flow a bit
  linux-user: init_guest_commpage: Add a comment about size check
  linux-user: init_guest_space: Clarify page alignment logic
  linux-user: init_guest_space: Correctly handle guest_start in commpage initialization
  linux-user: init_guest_space: Clean up if we can't initialize the commpage
  linux-user: Rename validate_guest_space => init_guest_commpage
  linux-user: Use #if to only call validate_guest_space for 32-bit ARM target
  qemu-binfmt-conf.sh: add qemu-xtensa
  linux-user: drop unused target_msync function
  linux-user: fix target_mprotect/target_munmap error return values
  linux-user: fix assertion in shmdt
  linux-user: fix mmap/munmap/mprotect/mremap/shmat
  linux-user: Support f_flags in statfs when available.
  linux-user: allows to use "--systemd ALL" with qemu-binfmt-conf.sh
  linux-user: Remove the unused "not implemented" signal handling stubs
  linux-user: Drop unicore32 code

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 65 insertions, 103 deletions

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5fc130cc20..9d10a5f592 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -354,7 +354,6 @@ enum {
 
 /* The commpage only exists for 32 bit kernels */
 
-#define TARGET_HAS_VALIDATE_GUEST_SPACE
 /* Return 1 if the proposed guest space is suitable for the guest.
  * Return 0 if the proposed guest space isn't suitable, but another
  * address space should be tried.
@@ -363,8 +362,8 @@ enum {
  * The guest code may leave a page mapped and populate it if the
  * address is suitable.
  */
-static int validate_guest_space(unsigned long guest_base,
-                                unsigned long guest_size)
+static int init_guest_commpage(unsigned long guest_base,
+                               unsigned long guest_size)
 {
     unsigned long real_start, test_page_addr;
 
@@ -375,6 +374,11 @@ static int validate_guest_space(unsigned long guest_base,
 
     /* If the commpage lies within the already allocated guest space,
      * then there is no way we can allocate it.
+     *
+     * You may be thinking that that this check is redundant because
+     * we already validated the guest size against MAX_RESERVED_VA;
+     * but if qemu_host_page_mask is unusually large, then
+     * test_page_addr may be lower.
      */
     if (test_page_addr >= guest_base
         && test_page_addr < (guest_base + guest_size)) {
@@ -563,78 +567,6 @@ static uint32_t get_elf_hwcap(void)
 #endif /* not TARGET_AARCH64 */
 #endif /* TARGET_ARM */
 
-#ifdef TARGET_UNICORE32
-
-#define ELF_START_MMAP          0x80000000
-
-#define ELF_CLASS               ELFCLASS32
-#define ELF_DATA                ELFDATA2LSB
-#define ELF_ARCH                EM_UNICORE32
-
-static inline void init_thread(struct target_pt_regs *regs,
-        struct image_info *infop)
-{
-    abi_long stack = infop->start_stack;
-    memset(regs, 0, sizeof(*regs));
-    regs->UC32_REG_asr = 0x10;
-    regs->UC32_REG_pc = infop->entry & 0xfffffffe;
-    regs->UC32_REG_sp = infop->start_stack;
-    /* FIXME - what to for failure of get_user()? */
-    get_user_ual(regs->UC32_REG_02, stack + 8); /* envp */
-    get_user_ual(regs->UC32_REG_01, stack + 4); /* envp */
-    /* XXX: it seems that r0 is zeroed after ! */
-    regs->UC32_REG_00 = 0;
-}
-
-#define ELF_NREG    34
-typedef target_elf_greg_t  target_elf_gregset_t[ELF_NREG];
-
-static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUUniCore32State *env)
-{
-    (*regs)[0] = env->regs[0];
-    (*regs)[1] = env->regs[1];
-    (*regs)[2] = env->regs[2];
-    (*regs)[3] = env->regs[3];
-    (*regs)[4] = env->regs[4];
-    (*regs)[5] = env->regs[5];
-    (*regs)[6] = env->regs[6];
-    (*regs)[7] = env->regs[7];
-    (*regs)[8] = env->regs[8];
-    (*regs)[9] = env->regs[9];
-    (*regs)[10] = env->regs[10];
-    (*regs)[11] = env->regs[11];
-    (*regs)[12] = env->regs[12];
-    (*regs)[13] = env->regs[13];
-    (*regs)[14] = env->regs[14];
-    (*regs)[15] = env->regs[15];
-    (*regs)[16] = env->regs[16];
-    (*regs)[17] = env->regs[17];
-    (*regs)[18] = env->regs[18];
-    (*regs)[19] = env->regs[19];
-    (*regs)[20] = env->regs[20];
-    (*regs)[21] = env->regs[21];
-    (*regs)[22] = env->regs[22];
-    (*regs)[23] = env->regs[23];
-    (*regs)[24] = env->regs[24];
-    (*regs)[25] = env->regs[25];
-    (*regs)[26] = env->regs[26];
-    (*regs)[27] = env->regs[27];
-    (*regs)[28] = env->regs[28];
-    (*regs)[29] = env->regs[29];
-    (*regs)[30] = env->regs[30];
-    (*regs)[31] = env->regs[31];
-
-    (*regs)[32] = cpu_asr_read((CPUUniCore32State *)env);
-    (*regs)[33] = env->regs[0]; /* XXX */
-}
-
-#define USE_ELF_CORE_DUMP
-#define ELF_EXEC_PAGESIZE               4096
-
-#define ELF_HWCAP                       (UC32_HWCAP_CMOV | UC32_HWCAP_UCF64)
-
-#endif
-
 #ifdef TARGET_SPARC
 #ifdef TARGET_SPARC64
 
@@ -1869,21 +1801,12 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
     return sp;
 }
 
-#ifndef TARGET_HAS_VALIDATE_GUEST_SPACE
-/* If the guest doesn't have a validation function just agree */
-static int validate_guest_space(unsigned long guest_base,
-                                unsigned long guest_size)
-{
-    return 1;
-}
-#endif
-
 unsigned long init_guest_space(unsigned long host_start,
                                unsigned long host_size,
                                unsigned long guest_start,
                                bool fixed)
 {
-    unsigned long current_start, real_start;
+    unsigned long current_start, aligned_start;
     int flags;
 
     assert(host_start || host_size);
@@ -1891,11 +1814,12 @@ unsigned long init_guest_space(unsigned long host_start,
     /* If just a starting address is given, then just verify that
      * address.  */
     if (host_start && !host_size) {
-        if (validate_guest_space(host_start, host_size) == 1) {
-            return host_start;
-        } else {
+#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
+        if (init_guest_commpage(host_start, host_size) != 1) {
             return (unsigned long)-1;
         }
+#endif
+        return host_start;
     }
 
     /* Setup the initial flags and start address.  */
@@ -1908,7 +1832,8 @@ unsigned long init_guest_space(unsigned long host_start,
     /* Otherwise, a non-zero size region of memory needs to be mapped
      * and validated.  */
     while (1) {
-        unsigned long real_size = host_size;
+        unsigned long real_start, real_size, aligned_size;
+        aligned_size = real_size = host_size;
 
         /* Do not use mmap_find_vma here because that is limited to the
          * guest address space.  We are going to make the
@@ -1920,30 +1845,63 @@ unsigned long init_guest_space(unsigned long host_start,
             return (unsigned long)-1;
         }
 
+        /* Check to see if the address is valid.  */
+        if (host_start && real_start != current_start) {
+            goto try_again;
+        }
+
         /* Ensure the address is properly aligned.  */
         if (real_start & ~qemu_host_page_mask) {
+            /* Ideally, we adjust like
+             *
+             *    pages: [  ][  ][  ][  ][  ]
+             *      old:   [   real   ]
+             *             [ aligned  ]
+             *      new:   [     real     ]
+             *               [ aligned  ]
+             *
+             * But if there is something else mapped right after it,
+             * then obviously it won't have room to grow, and the
+             * kernel will put the new larger real someplace else with
+             * unknown alignment (if we made it to here, then
+             * fixed=false).  Which is why we grow real by a full page
+             * size, instead of by part of one; so that even if we get
+             * moved, we can still guarantee alignment.  But this does
+             * mean that there is a padding of < 1 page both before
+             * and after the aligned range; the "after" could could
+             * cause problems for ARM emulation where it could butt in
+             * to where we need to put the commpage.
+             */
             munmap((void *)real_start, host_size);
-            real_size = host_size + qemu_host_page_size;
+            real_size = aligned_size + qemu_host_page_size;
             real_start = (unsigned long)
                 mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0);
             if (real_start == (unsigned long)-1) {
                 return (unsigned long)-1;
             }
-            real_start = HOST_PAGE_ALIGN(real_start);
+            aligned_start = HOST_PAGE_ALIGN(real_start);
+        } else {
+            aligned_start = real_start;
         }
 
-        /* Check to see if the address is valid.  */
-        if (!host_start || real_start == current_start) {
-            int valid = validate_guest_space(real_start - guest_start,
-                                             real_size);
-            if (valid == 1) {
-                break;
-            } else if (valid == -1) {
-                return (unsigned long)-1;
-            }
-            /* valid == 0, so try again. */
+#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
+        /* On 32-bit ARM, we need to also be able to map the commpage.  */
+        int valid = init_guest_commpage(aligned_start - guest_start,
+                                        aligned_size + guest_start);
+        if (valid == -1) {
+            munmap((void *)real_start, real_size);
+            return (unsigned long)-1;
+        } else if (valid == 0) {
+            goto try_again;
         }
+#endif
+
+        /* If nothing has said `return -1` or `goto try_again` yet,
+         * then the address we have is good.
+         */
+        break;
 
+    try_again:
         /* That address didn't work.  Unmap and try a different one.
          * The address the host picked because is typically right at
          * the top of the host address space and leaves the guest with
@@ -1952,8 +1910,12 @@ unsigned long init_guest_space(unsigned long host_start,
          * happen often.  Probably means we got unlucky and host
          * address space randomization put a shared library somewhere
          * inconvenient.
+         *
+         * This is probably a good strategy if host_start, but is
+         * probably a bad strategy if not, which means we got here
+         * because of trouble with ARM commpage setup.
          */
-        munmap((void *)real_start, host_size);
+        munmap((void *)real_start, real_size);
         current_start += qemu_host_page_size;
         if (host_start == current_start) {
             /* Theoretically possible if host doesn't have any suitably
@@ -1965,7 +1927,7 @@ unsigned long init_guest_space(unsigned long host_start,
 
     qemu_log_mask(CPU_LOG_PAGE, "Reserved 0x%lx bytes of guest address space\n", host_size);
 
-    return real_start;
+    return aligned_start;
 }
 
 static void probe_guest_base(const char *image_name,