[PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Richard Henderson]

Supercedes: 20230804014517.6361-1-richard.henderson@linaro.org
("[PATCH for-8.1 v8 00/17] linux-user: brk fixes")

Changes for linux-user brk v9:
  Recover some changes that should have been in v8, had I
  generated the patches from the correct tree:
    - bsd-user: Remove last_brk
    - Fix typos in patch 15 ("Define ELF_ET_DYN_BASE...")
    - Disable -Werror=type-limits in patch 13
      ("linux-user: Adjust task_unmapped_base")


r~


Akihiko Odaki (6):
  linux-user: Unset MAP_FIXED_NOREPLACE for host
  linux-user: Fix MAP_FIXED_NOREPLACE on old kernels
  linux-user: Do not call get_errno() in do_brk()
  linux-user: Use MAP_FIXED_NOREPLACE for do_brk()
  linux-user: Do nothing if too small brk is specified
  linux-user: Do not align brk with host page size

Helge Deller (1):
  linux-user: Adjust initial brk when interpreter is close to executable

Matheus Tavares Bernardino (1):
  gdbstub: use 0 ("any process") on packets with no PID

Mikhail Tyutin (1):
  accel/tcg: Call save_iotlb_data from io_readx as well.

Nathan Egge (1):
  linux-user/elfload: Set V in ELF_HWCAP for RISC-V

Richard Henderson (14):
  accel/tcg: Adjust parameters and locking with do_{ld,st}_mmio_*
  accel/tcg: Issue wider aligned i/o in do_{ld,st}_mmio_*
  accel/tcg: Do not issue misaligned i/o
  linux-user: Remove last_brk
  bsd-user: Remove last_brk
  linux-user: Adjust task_unmapped_base for reserved_va
  linux-user: Define TASK_UNMAPPED_BASE in $guest/target_mman.h
  linux-user: Define ELF_ET_DYN_BASE in $guest/target_mman.h
  linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap
  linux-user: Use elf_et_dyn_base for ET_DYN with interpreter
  linux-user: Properly set image_info.brk in flatload
  linux-user: Do not adjust image mapping for host page size
  linux-user: Do not adjust zero_bss for host page size
  linux-user: Use zero_bss for PT_LOAD with no file contents too

 bsd-user/qemu.h                      |   1 -
 linux-user/aarch64/target_mman.h     |  13 ++
 linux-user/alpha/target_mman.h       |  11 +
 linux-user/arm/target_mman.h         |  11 +
 linux-user/cris/target_mman.h        |  12 ++
 linux-user/hexagon/target_mman.h     |  13 ++
 linux-user/hppa/target_mman.h        |   6 +
 linux-user/i386/target_mman.h        |  16 ++
 linux-user/loongarch64/target_mman.h |  11 +
 linux-user/m68k/target_mman.h        |   5 +
 linux-user/microblaze/target_mman.h  |  11 +
 linux-user/mips/target_mman.h        |  10 +
 linux-user/nios2/target_mman.h       |  10 +
 linux-user/openrisc/target_mman.h    |  10 +
 linux-user/ppc/target_mman.h         |  20 ++
 linux-user/qemu.h                    |   2 -
 linux-user/riscv/target_mman.h       |  10 +
 linux-user/s390x/target_mman.h       |  20 ++
 linux-user/sh4/target_mman.h         |   7 +
 linux-user/sparc/target_mman.h       |  25 +++
 linux-user/user-mmap.h               |   6 +-
 linux-user/x86_64/target_mman.h      |  15 ++
 linux-user/xtensa/target_mman.h      |  10 +
 accel/tcg/cputlb.c                   | 289 ++++++++++++++++++---------
 bsd-user/mmap.c                      |   2 -
 gdbstub/gdbstub.c                    |   2 +-
 linux-user/elfload.c                 | 184 ++++++++---------
 linux-user/flatload.c                |   2 +-
 linux-user/main.c                    |  45 ++++-
 linux-user/mmap.c                    |  68 ++++---
 linux-user/syscall.c                 |  69 ++-----
 31 files changed, 622 insertions(+), 294 deletions(-)

-- 
2.34.1

[PATCH v9 01/24] accel/tcg: Adjust parameters and locking with do_{ld, st}_mmio_*

[Richard Henderson]

Replace MMULookupPageData* with CPUTLBEntryFull, addr, size.
Move QEMU_IOTHREAD_LOCK_GUARD to the caller.

This simplifies the usage from do_ld16_beN and do_st16_leN, where
we weren't locking the entire operation, and required hoop jumping
for passing addr and size.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 67 +++++++++++++++++++++++-----------------------
 1 file changed, 34 insertions(+), 33 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index ba44501a7c..23386ecfde 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -2066,24 +2066,22 @@ static void *atomic_mmu_lookup(CPUArchState *env, vaddr addr, MemOpIdx oi,
 /**
  * do_ld_mmio_beN:
  * @env: cpu context
- * @p: translation parameters
+ * @full: page parameters
  * @ret_be: accumulated data
+ * @addr: virtual address
+ * @size: number of bytes
  * @mmu_idx: virtual address context
  * @ra: return address into tcg generated code, or 0
+ * Context: iothread lock held
  *
- * Load @p->size bytes from @p->addr, which is memory-mapped i/o.
+ * Load @size bytes from @addr, which is memory-mapped i/o.
  * The bytes are concatenated in big-endian order with @ret_be.
  */
-static uint64_t do_ld_mmio_beN(CPUArchState *env, MMULookupPageData *p,
-                               uint64_t ret_be, int mmu_idx,
-                               MMUAccessType type, uintptr_t ra)
+static uint64_t do_ld_mmio_beN(CPUArchState *env, CPUTLBEntryFull *full,
+                               uint64_t ret_be, vaddr addr, int size,
+                               int mmu_idx, MMUAccessType type, uintptr_t ra)
 {
-    CPUTLBEntryFull *full = p->full;
-    vaddr addr = p->addr;
-    int i, size = p->size;
-
-    QEMU_IOTHREAD_LOCK_GUARD();
-    for (i = 0; i < size; i++) {
+    for (int i = 0; i < size; i++) {
         uint8_t x = io_readx(env, full, mmu_idx, addr + i, ra, type, MO_UB);
         ret_be = (ret_be << 8) | x;
     }
@@ -2232,7 +2230,9 @@ static uint64_t do_ld_beN(CPUArchState *env, MMULookupPageData *p,
     unsigned tmp, half_size;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        return do_ld_mmio_beN(env, p, ret_be, mmu_idx, type, ra);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        return do_ld_mmio_beN(env, p->full, ret_be, p->addr, p->size,
+                              mmu_idx, type, ra);
     }
 
     /*
@@ -2281,11 +2281,11 @@ static Int128 do_ld16_beN(CPUArchState *env, MMULookupPageData *p,
     MemOp atom;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        p->size = size - 8;
-        a = do_ld_mmio_beN(env, p, a, mmu_idx, MMU_DATA_LOAD, ra);
-        p->addr += p->size;
-        p->size = 8;
-        b = do_ld_mmio_beN(env, p, 0, mmu_idx, MMU_DATA_LOAD, ra);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        a = do_ld_mmio_beN(env, p->full, a, p->addr, size - 8,
+                           mmu_idx, MMU_DATA_LOAD, ra);
+        b = do_ld_mmio_beN(env, p->full, 0, p->addr + 8, 8,
+                           mmu_idx, MMU_DATA_LOAD, ra);
         return int128_make128(b, a);
     }
 
@@ -2664,24 +2664,23 @@ Int128 cpu_ld16_mmu(CPUArchState *env, abi_ptr addr,
 /**
  * do_st_mmio_leN:
  * @env: cpu context
- * @p: translation parameters
+ * @full: page parameters
  * @val_le: data to store
+ * @addr: virtual address
+ * @size: number of bytes
  * @mmu_idx: virtual address context
  * @ra: return address into tcg generated code, or 0
+ * Context: iothread lock held
  *
- * Store @p->size bytes at @p->addr, which is memory-mapped i/o.
+ * Store @size bytes at @addr, which is memory-mapped i/o.
  * The bytes to store are extracted in little-endian order from @val_le;
  * return the bytes of @val_le beyond @p->size that have not been stored.
  */
-static uint64_t do_st_mmio_leN(CPUArchState *env, MMULookupPageData *p,
-                               uint64_t val_le, int mmu_idx, uintptr_t ra)
+static uint64_t do_st_mmio_leN(CPUArchState *env, CPUTLBEntryFull *full,
+                               uint64_t val_le, vaddr addr, int size,
+                               int mmu_idx, uintptr_t ra)
 {
-    CPUTLBEntryFull *full = p->full;
-    vaddr addr = p->addr;
-    int i, size = p->size;
-
-    QEMU_IOTHREAD_LOCK_GUARD();
-    for (i = 0; i < size; i++, val_le >>= 8) {
+    for (int i = 0; i < size; i++, val_le >>= 8) {
         io_writex(env, full, mmu_idx, val_le, addr + i, ra, MO_UB);
     }
     return val_le;
@@ -2698,7 +2697,9 @@ static uint64_t do_st_leN(CPUArchState *env, MMULookupPageData *p,
     unsigned tmp, half_size;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        return do_st_mmio_leN(env, p, val_le, mmu_idx, ra);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        return do_st_mmio_leN(env, p->full, val_le, p->addr,
+                              p->size, mmu_idx, ra);
     } else if (unlikely(p->flags & TLB_DISCARD_WRITE)) {
         return val_le >> (p->size * 8);
     }
@@ -2751,11 +2752,11 @@ static uint64_t do_st16_leN(CPUArchState *env, MMULookupPageData *p,
     MemOp atom;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        p->size = 8;
-        do_st_mmio_leN(env, p, int128_getlo(val_le), mmu_idx, ra);
-        p->size = size - 8;
-        p->addr += 8;
-        return do_st_mmio_leN(env, p, int128_gethi(val_le), mmu_idx, ra);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        do_st_mmio_leN(env, p->full, int128_getlo(val_le),
+                       p->addr, 8, mmu_idx, ra);
+        return do_st_mmio_leN(env, p->full, int128_gethi(val_le),
+                              p->addr + 8, size - 8, mmu_idx, ra);
     } else if (unlikely(p->flags & TLB_DISCARD_WRITE)) {
         return int128_gethi(val_le) >> ((size - 8) * 8);
     }
-- 
2.34.1

[PATCH v9 02/24] accel/tcg: Issue wider aligned i/o in do_{ld, st}_mmio_*

[Richard Henderson]

If the address and size are aligned, send larger chunks
to the memory subsystem.  This will be required to make
more use of these helpers.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 76 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 69 insertions(+), 7 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 23386ecfde..a308cb7534 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -2081,10 +2081,40 @@ static uint64_t do_ld_mmio_beN(CPUArchState *env, CPUTLBEntryFull *full,
                                uint64_t ret_be, vaddr addr, int size,
                                int mmu_idx, MMUAccessType type, uintptr_t ra)
 {
-    for (int i = 0; i < size; i++) {
-        uint8_t x = io_readx(env, full, mmu_idx, addr + i, ra, type, MO_UB);
-        ret_be = (ret_be << 8) | x;
-    }
+    uint64_t t;
+
+    tcg_debug_assert(size > 0 && size <= 8);
+    do {
+        /* Read aligned pieces up to 8 bytes. */
+        switch ((size | (int)addr) & 7) {
+        case 1:
+        case 3:
+        case 5:
+        case 7:
+            t = io_readx(env, full, mmu_idx, addr, ra, type, MO_UB);
+            ret_be = (ret_be << 8) | t;
+            size -= 1;
+            addr += 1;
+            break;
+        case 2:
+        case 6:
+            t = io_readx(env, full, mmu_idx, addr, ra, type, MO_BEUW);
+            ret_be = (ret_be << 16) | t;
+            size -= 2;
+            addr += 2;
+            break;
+        case 4:
+            t = io_readx(env, full, mmu_idx, addr, ra, type, MO_BEUL);
+            ret_be = (ret_be << 32) | t;
+            size -= 4;
+            addr += 4;
+            break;
+        case 0:
+            return io_readx(env, full, mmu_idx, addr, ra, type, MO_BEUQ);
+        default:
+            qemu_build_not_reached();
+        }
+    } while (size);
     return ret_be;
 }
 
@@ -2680,9 +2710,41 @@ static uint64_t do_st_mmio_leN(CPUArchState *env, CPUTLBEntryFull *full,
                                uint64_t val_le, vaddr addr, int size,
                                int mmu_idx, uintptr_t ra)
 {
-    for (int i = 0; i < size; i++, val_le >>= 8) {
-        io_writex(env, full, mmu_idx, val_le, addr + i, ra, MO_UB);
-    }
+    tcg_debug_assert(size > 0 && size <= 8);
+
+    do {
+        /* Store aligned pieces up to 8 bytes. */
+        switch ((size | (int)addr) & 7) {
+        case 1:
+        case 3:
+        case 5:
+        case 7:
+            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_UB);
+            val_le >>= 8;
+            size -= 1;
+            addr += 1;
+            break;
+        case 2:
+        case 6:
+            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUW);
+            val_le >>= 16;
+            size -= 2;
+            addr += 2;
+            break;
+        case 4:
+            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUL);
+            val_le >>= 32;
+            size -= 4;
+            addr += 4;
+            break;
+        case 0:
+            io_writex(env, full, mmu_idx, val_le, addr, ra, MO_LEUQ);
+            return 0;
+        default:
+            qemu_build_not_reached();
+        }
+    } while (size);
+
     return val_le;
 }
 
-- 
2.34.1

[PATCH v9 03/24] accel/tcg: Do not issue misaligned i/o

[Richard Henderson]

In the single-page case we were issuing misaligned i/o to
the memory subsystem, which does not handle it properly.
Split such accesses via do_{ld,st}_mmio_*.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1800
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 118 +++++++++++++++++++++++++++------------------
 1 file changed, 72 insertions(+), 46 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index a308cb7534..4b1bfaa53d 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -2370,16 +2370,20 @@ static uint8_t do_ld_1(CPUArchState *env, MMULookupPageData *p, int mmu_idx,
 static uint16_t do_ld_2(CPUArchState *env, MMULookupPageData *p, int mmu_idx,
                         MMUAccessType type, MemOp memop, uintptr_t ra)
 {
-    uint64_t ret;
+    uint16_t ret;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        return io_readx(env, p->full, mmu_idx, p->addr, ra, type, memop);
-    }
-
-    /* Perform the load host endian, then swap if necessary. */
-    ret = load_atom_2(env, ra, p->haddr, memop);
-    if (memop & MO_BSWAP) {
-        ret = bswap16(ret);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        ret = do_ld_mmio_beN(env, p->full, 0, p->addr, 2, mmu_idx, type, ra);
+        if ((memop & MO_BSWAP) == MO_LE) {
+            ret = bswap16(ret);
+        }
+    } else {
+        /* Perform the load host endian, then swap if necessary. */
+        ret = load_atom_2(env, ra, p->haddr, memop);
+        if (memop & MO_BSWAP) {
+            ret = bswap16(ret);
+        }
     }
     return ret;
 }
@@ -2390,13 +2394,17 @@ static uint32_t do_ld_4(CPUArchState *env, MMULookupPageData *p, int mmu_idx,
     uint32_t ret;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        return io_readx(env, p->full, mmu_idx, p->addr, ra, type, memop);
-    }
-
-    /* Perform the load host endian. */
-    ret = load_atom_4(env, ra, p->haddr, memop);
-    if (memop & MO_BSWAP) {
-        ret = bswap32(ret);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        ret = do_ld_mmio_beN(env, p->full, 0, p->addr, 4, mmu_idx, type, ra);
+        if ((memop & MO_BSWAP) == MO_LE) {
+            ret = bswap32(ret);
+        }
+    } else {
+        /* Perform the load host endian. */
+        ret = load_atom_4(env, ra, p->haddr, memop);
+        if (memop & MO_BSWAP) {
+            ret = bswap32(ret);
+        }
     }
     return ret;
 }
@@ -2407,13 +2415,17 @@ static uint64_t do_ld_8(CPUArchState *env, MMULookupPageData *p, int mmu_idx,
     uint64_t ret;
 
     if (unlikely(p->flags & TLB_MMIO)) {
-        return io_readx(env, p->full, mmu_idx, p->addr, ra, type, memop);
-    }
-
-    /* Perform the load host endian. */
-    ret = load_atom_8(env, ra, p->haddr, memop);
-    if (memop & MO_BSWAP) {
-        ret = bswap64(ret);
+        QEMU_IOTHREAD_LOCK_GUARD();
+        ret = do_ld_mmio_beN(env, p->full, 0, p->addr, 8, mmu_idx, type, ra);
+        if ((memop & MO_BSWAP) == MO_LE) {
+            ret = bswap64(ret);
+        }
+    } else {
+        /* Perform the load host endian. */
+        ret = load_atom_8(env, ra, p->haddr, memop);
+        if (memop & MO_BSWAP) {
+            ret = bswap64(ret);
+        }
     }
     return ret;
 }
@@ -2561,20 +2573,22 @@ static Int128 do_ld16_mmu(CPUArchState *env, vaddr addr,
     cpu_req_mo(TCG_MO_LD_LD | TCG_MO_ST_LD);
     crosspage = mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD, &l);
     if (likely(!crosspage)) {
-        /* Perform the load host endian. */
         if (unlikely(l.page[0].flags & TLB_MMIO)) {
             QEMU_IOTHREAD_LOCK_GUARD();
-            a = io_readx(env, l.page[0].full, l.mmu_idx, addr,
-                         ra, MMU_DATA_LOAD, MO_64);
-            b = io_readx(env, l.page[0].full, l.mmu_idx, addr + 8,
-                         ra, MMU_DATA_LOAD, MO_64);
-            ret = int128_make128(HOST_BIG_ENDIAN ? b : a,
-                                 HOST_BIG_ENDIAN ? a : b);
+            a = do_ld_mmio_beN(env, l.page[0].full, 0, addr, 8,
+                               l.mmu_idx, MMU_DATA_LOAD, ra);
+            b = do_ld_mmio_beN(env, l.page[0].full, 0, addr + 8, 8,
+                               l.mmu_idx, MMU_DATA_LOAD, ra);
+            ret = int128_make128(b, a);
+            if ((l.memop & MO_BSWAP) == MO_LE) {
+                ret = bswap128(ret);
+            }
         } else {
+            /* Perform the load host endian. */
             ret = load_atom_16(env, ra, l.page[0].haddr, l.memop);
-        }
-        if (l.memop & MO_BSWAP) {
-            ret = bswap128(ret);
+            if (l.memop & MO_BSWAP) {
+                ret = bswap128(ret);
+            }
         }
         return ret;
     }
@@ -2874,7 +2888,11 @@ static void do_st_2(CPUArchState *env, MMULookupPageData *p, uint16_t val,
                     int mmu_idx, MemOp memop, uintptr_t ra)
 {
     if (unlikely(p->flags & TLB_MMIO)) {
-        io_writex(env, p->full, mmu_idx, val, p->addr, ra, memop);
+        if ((memop & MO_BSWAP) != MO_LE) {
+            val = bswap16(val);
+        }
+        QEMU_IOTHREAD_LOCK_GUARD();
+        do_st_mmio_leN(env, p->full, val, p->addr, 2, mmu_idx, ra);
     } else if (unlikely(p->flags & TLB_DISCARD_WRITE)) {
         /* nothing */
     } else {
@@ -2890,7 +2908,11 @@ static void do_st_4(CPUArchState *env, MMULookupPageData *p, uint32_t val,
                     int mmu_idx, MemOp memop, uintptr_t ra)
 {
     if (unlikely(p->flags & TLB_MMIO)) {
-        io_writex(env, p->full, mmu_idx, val, p->addr, ra, memop);
+        if ((memop & MO_BSWAP) != MO_LE) {
+            val = bswap32(val);
+        }
+        QEMU_IOTHREAD_LOCK_GUARD();
+        do_st_mmio_leN(env, p->full, val, p->addr, 4, mmu_idx, ra);
     } else if (unlikely(p->flags & TLB_DISCARD_WRITE)) {
         /* nothing */
     } else {
@@ -2906,7 +2928,11 @@ static void do_st_8(CPUArchState *env, MMULookupPageData *p, uint64_t val,
                     int mmu_idx, MemOp memop, uintptr_t ra)
 {
     if (unlikely(p->flags & TLB_MMIO)) {
-        io_writex(env, p->full, mmu_idx, val, p->addr, ra, memop);
+        if ((memop & MO_BSWAP) != MO_LE) {
+            val = bswap64(val);
+        }
+        QEMU_IOTHREAD_LOCK_GUARD();
+        do_st_mmio_leN(env, p->full, val, p->addr, 8, mmu_idx, ra);
     } else if (unlikely(p->flags & TLB_DISCARD_WRITE)) {
         /* nothing */
     } else {
@@ -3029,22 +3055,22 @@ static void do_st16_mmu(CPUArchState *env, vaddr addr, Int128 val,
     cpu_req_mo(TCG_MO_LD_ST | TCG_MO_ST_ST);
     crosspage = mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE, &l);
     if (likely(!crosspage)) {
-        /* Swap to host endian if necessary, then store. */
-        if (l.memop & MO_BSWAP) {
-            val = bswap128(val);
-        }
         if (unlikely(l.page[0].flags & TLB_MMIO)) {
-            QEMU_IOTHREAD_LOCK_GUARD();
-            if (HOST_BIG_ENDIAN) {
-                b = int128_getlo(val), a = int128_gethi(val);
-            } else {
-                a = int128_getlo(val), b = int128_gethi(val);
+            if ((l.memop & MO_BSWAP) != MO_LE) {
+                val = bswap128(val);
             }
-            io_writex(env, l.page[0].full, l.mmu_idx, a, addr, ra, MO_64);
-            io_writex(env, l.page[0].full, l.mmu_idx, b, addr + 8, ra, MO_64);
+            a = int128_getlo(val);
+            b = int128_gethi(val);
+            QEMU_IOTHREAD_LOCK_GUARD();
+            do_st_mmio_leN(env, l.page[0].full, a, addr, 8, l.mmu_idx, ra);
+            do_st_mmio_leN(env, l.page[0].full, b, addr + 8, 8, l.mmu_idx, ra);
         } else if (unlikely(l.page[0].flags & TLB_DISCARD_WRITE)) {
             /* nothing */
         } else {
+            /* Swap to host endian if necessary, then store. */
+            if (l.memop & MO_BSWAP) {
+                val = bswap128(val);
+            }
             store_atom_16(env, ra, l.page[0].haddr, l.memop, val);
         }
         return;
-- 
2.34.1

[PATCH v9 04/24] gdbstub: use 0 ("any process") on packets with no PID

[Richard Henderson]

From: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>

Previously, qemu-user would always report PID 1 to GDB. This was changed
at dc14a7a6e9 (gdbstub: Report the actual qemu-user pid, 2023-06-30),
but read_thread_id() still considers GDB packets with "no PID" as "PID
1", which is not the qemu-user PID. Fix that by parsing "no PID" as "0",
which the GDB Remote Protocol defines as "any process".

Note that this should have no effect for system emulation as, in this
case, gdb_create_default_process() will assign PID 1 for the first
process and that is what the gdbstub uses for GDB requests with no PID,
or PID 0.

This issue was found with hexagon-lldb, which sends a "Hg" packet with
only the thread-id, but no process-id, leading to the invalid usage of
"PID 1" by qemu-hexagon and a subsequent "E22" reply.

Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <78a3b06f6ab90a7ff8e73ae14a996eb27ec76c85.1690904195.git.quic_mathbern@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 gdbstub/gdbstub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index ce8b42eb15..e74ecc78cc 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -537,7 +537,7 @@ static GDBThreadIdKind read_thread_id(const char *buf, const char **end_buf,
         /* Skip '.' */
         buf++;
     } else {
-        p = 1;
+        p = 0;
     }
 
     ret = qemu_strtoul(buf, &buf, 16, &t);
-- 
2.34.1

[PATCH v9 05/24] linux-user: Unset MAP_FIXED_NOREPLACE for host

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Passing MAP_FIXED_NOREPLACE to host will fail for reserved_va because
the address space is reserved with mmap.  Replace it with MAP_FIXED
in that case.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-2-akihiko.odaki@daynix.com>
[rth: Expand inline commentary.]
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/mmap.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index a5dfb56545..a11c630a7b 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -603,11 +603,26 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
             goto fail;
         }
 
-        /* Validate that the chosen range is empty. */
-        if ((flags & MAP_FIXED_NOREPLACE)
-            && !page_check_range_empty(start, last)) {
-            errno = EEXIST;
-            goto fail;
+        if (flags & MAP_FIXED_NOREPLACE) {
+            /* Validate that the chosen range is empty. */
+            if (!page_check_range_empty(start, last)) {
+                errno = EEXIST;
+                goto fail;
+            }
+
+            /*
+             * With reserved_va, the entire address space is mmaped in the
+             * host to ensure it isn't accidentally used for something else.
+             * We have just checked that the guest address is not mapped
+             * within the guest, but need to replace the host reservation.
+             *
+             * Without reserved_va, despite the guest address check above,
+             * keep MAP_FIXED_NOREPLACE so that the guest does not overwrite
+             * any host address mappings.
+             */
+            if (reserved_va) {
+                flags = (flags & ~MAP_FIXED_NOREPLACE) | MAP_FIXED;
+            }
         }
 
         /*
-- 
2.34.1

[PATCH v9 06/24] linux-user: Fix MAP_FIXED_NOREPLACE on old kernels

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

The man page states:
> Note that older kernels which do not recognize the MAP_FIXED_NOREPLACE
> flag will typically (upon detecting a collision with a preexisting
> mapping) fall back to a “non-MAP_FIXED” type of behavior: they will
> return an address that is different from the requested address.
> Therefore, backward-compatible software should check the returned
> address against the requested address.
https://man7.org/linux/man-pages/man2/mmap.2.html

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-3-akihiko.odaki@daynix.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/mmap.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index a11c630a7b..90b3ef2140 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -263,7 +263,11 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
         void *p = mmap(host_start, qemu_host_page_size,
                        target_to_host_prot(prot),
                        flags | MAP_ANONYMOUS, -1, 0);
-        if (p == MAP_FAILED) {
+        if (p != host_start) {
+            if (p != MAP_FAILED) {
+                munmap(p, qemu_host_page_size);
+                errno = EEXIST;
+            }
             return false;
         }
         prot_old = prot;
@@ -687,17 +691,25 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
 
         /* map the middle (easier) */
         if (real_start < real_last) {
-            void *p;
+            void *p, *want_p;
             off_t offset1;
+            size_t len1;
 
             if (flags & MAP_ANONYMOUS) {
                 offset1 = 0;
             } else {
                 offset1 = offset + real_start - start;
             }
-            p = mmap(g2h_untagged(real_start), real_last - real_start + 1,
-                     target_to_host_prot(target_prot), flags, fd, offset1);
-            if (p == MAP_FAILED) {
+            len1 = real_last - real_start + 1;
+            want_p = g2h_untagged(real_start);
+
+            p = mmap(want_p, len1, target_to_host_prot(target_prot),
+                     flags, fd, offset1);
+            if (p != want_p) {
+                if (p != MAP_FAILED) {
+                    munmap(p, len1);
+                    errno = EEXIST;
+                }
                 goto fail;
             }
             passthrough_start = real_start;
-- 
2.34.1

[PATCH v9 07/24] linux-user: Do not call get_errno() in do_brk()

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Later the returned value is compared with -1, and negated errno is not
expected.

Fixes: 00faf08c95 ("linux-user: Don't use MAP_FIXED in do_brk()")
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-4-akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 95727a816a..b9d2ec02f9 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -862,9 +862,9 @@ abi_long do_brk(abi_ulong brk_val)
      */
     if (new_host_brk_page > brk_page) {
         new_alloc_size = new_host_brk_page - brk_page;
-        mapped_addr = get_errno(target_mmap(brk_page, new_alloc_size,
-                                        PROT_READ|PROT_WRITE,
-                                        MAP_ANON|MAP_PRIVATE, 0, 0));
+        mapped_addr = target_mmap(brk_page, new_alloc_size,
+                                  PROT_READ|PROT_WRITE,
+                                  MAP_ANON|MAP_PRIVATE, 0, 0);
     } else {
         new_alloc_size = 0;
         mapped_addr = brk_page;
-- 
2.34.1

[PATCH v9 08/24] linux-user: Use MAP_FIXED_NOREPLACE for do_brk()

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

MAP_FIXED_NOREPLACE can ensure the mapped address is fixed without
concerning that the new mapping overwrites something else.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-5-akihiko.odaki@daynix.com>
[rth: Pass -1 as fd for MAP_ANON]
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index b9d2ec02f9..f64024273f 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -854,17 +854,12 @@ abi_long do_brk(abi_ulong brk_val)
         return target_brk;
     }
 
-    /* We need to allocate more memory after the brk... Note that
-     * we don't use MAP_FIXED because that will map over the top of
-     * any existing mapping (like the one with the host libc or qemu
-     * itself); instead we treat "mapped but at wrong address" as
-     * a failure and unmap again.
-     */
     if (new_host_brk_page > brk_page) {
         new_alloc_size = new_host_brk_page - brk_page;
         mapped_addr = target_mmap(brk_page, new_alloc_size,
-                                  PROT_READ|PROT_WRITE,
-                                  MAP_ANON|MAP_PRIVATE, 0, 0);
+                                  PROT_READ | PROT_WRITE,
+                                  MAP_FIXED_NOREPLACE | MAP_ANON | MAP_PRIVATE,
+                                  -1, 0);
     } else {
         new_alloc_size = 0;
         mapped_addr = brk_page;
@@ -883,12 +878,6 @@ abi_long do_brk(abi_ulong brk_val)
         target_brk = brk_val;
         brk_page = new_host_brk_page;
         return target_brk;
-    } else if (mapped_addr != -1) {
-        /* Mapped but at wrong address, meaning there wasn't actually
-         * enough space for this brk.
-         */
-        target_munmap(mapped_addr, new_alloc_size);
-        mapped_addr = -1;
     }
 
 #if defined(TARGET_ALPHA)
-- 
2.34.1

[PATCH v9 09/24] linux-user: Do nothing if too small brk is specified

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Linux 6.4.7 does nothing when a value smaller than the initial brk is
specified.

Fixes: 86f04735ac ("linux-user: Fix brk() to release pages")
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-6-akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index f64024273f..e1436a3962 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -820,14 +820,14 @@ abi_long do_brk(abi_ulong brk_val)
 
     /* brk pointers are always untagged */
 
-    /* return old brk value if brk_val unchanged or zero */
-    if (!brk_val || brk_val == target_brk) {
+    /* return old brk value if brk_val unchanged */
+    if (brk_val == target_brk) {
         return target_brk;
     }
 
     /* do not allow to shrink below initial brk value */
     if (brk_val < initial_target_brk) {
-        brk_val = initial_target_brk;
+        return target_brk;
     }
 
     new_brk = TARGET_PAGE_ALIGN(brk_val);
-- 
2.34.1

[PATCH v9 10/24] linux-user: Do not align brk with host page size

[Richard Henderson]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

do_brk() minimizes calls into target_mmap() by aligning the address
with host page size, which is potentially larger than the target page
size. However, the current implementation of this optimization has two
bugs:

- The start of brk is rounded up with the host page size while brk
  advertises an address aligned with the target page size as the
  beginning of brk. This makes the beginning of brk unmapped.
- Content clearing after mapping is flawed. The size to clear is
  specified as HOST_PAGE_ALIGN(brk_page) - brk_page, but brk_page is
  aligned with the host page size so it is always zero.

This optimization actually has no practical benefit. It makes difference
when brk() is called multiple times with values in a range of the host
page size. However, sophisticated memory allocators try to avoid to
make such frequent brk() calls. For example, glibc 2.37 calls brk() to
shrink the heap only when there is a room more than 128 KiB. It is
rare to have a page size larger than 128 KiB if it happens.

Let's remove the optimization to fix the bugs and make the code simpler.

Fixes: 86f04735ac ("linux-user: Fix brk() to release pages")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1616
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230802071754.14876-7-akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c |  4 ++--
 linux-user/syscall.c | 54 ++++++++++----------------------------------
 2 files changed, 14 insertions(+), 44 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 861ec07abc..2aee2298ec 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3678,8 +3678,8 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
      * to mmap pages in this space.
      */
     if (info->reserve_brk) {
-        abi_ulong start_brk = HOST_PAGE_ALIGN(info->brk);
-        abi_ulong end_brk = HOST_PAGE_ALIGN(info->brk + info->reserve_brk);
+        abi_ulong start_brk = TARGET_PAGE_ALIGN(info->brk);
+        abi_ulong end_brk = TARGET_PAGE_ALIGN(info->brk + info->reserve_brk);
         target_munmap(start_brk, end_brk - start_brk);
     }
 
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e1436a3962..7c2c2f6e2f 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -802,81 +802,51 @@ static inline int host_to_target_sock_type(int host_type)
 }
 
 static abi_ulong target_brk, initial_target_brk;
-static abi_ulong brk_page;
 
 void target_set_brk(abi_ulong new_brk)
 {
     target_brk = TARGET_PAGE_ALIGN(new_brk);
     initial_target_brk = target_brk;
-    brk_page = HOST_PAGE_ALIGN(target_brk);
 }
 
 /* do_brk() must return target values and target errnos. */
 abi_long do_brk(abi_ulong brk_val)
 {
     abi_long mapped_addr;
-    abi_ulong new_alloc_size;
-    abi_ulong new_brk, new_host_brk_page;
+    abi_ulong new_brk;
+    abi_ulong old_brk;
 
     /* brk pointers are always untagged */
 
-    /* return old brk value if brk_val unchanged */
-    if (brk_val == target_brk) {
-        return target_brk;
-    }
-
     /* do not allow to shrink below initial brk value */
     if (brk_val < initial_target_brk) {
         return target_brk;
     }
 
     new_brk = TARGET_PAGE_ALIGN(brk_val);
-    new_host_brk_page = HOST_PAGE_ALIGN(brk_val);
+    old_brk = TARGET_PAGE_ALIGN(target_brk);
 
-    /* brk_val and old target_brk might be on the same page */
-    if (new_brk == TARGET_PAGE_ALIGN(target_brk)) {
-        /* empty remaining bytes in (possibly larger) host page */
-        memset(g2h_untagged(new_brk), 0, new_host_brk_page - new_brk);
+    /* new and old target_brk might be on the same page */
+    if (new_brk == old_brk) {
         target_brk = brk_val;
         return target_brk;
     }
 
     /* Release heap if necesary */
-    if (new_brk < target_brk) {
-        /* empty remaining bytes in (possibly larger) host page */
-        memset(g2h_untagged(new_brk), 0, new_host_brk_page - new_brk);
-
-        /* free unused host pages and set new brk_page */
-        target_munmap(new_host_brk_page, brk_page - new_host_brk_page);
-        brk_page = new_host_brk_page;
+    if (new_brk < old_brk) {
+        target_munmap(new_brk, old_brk - new_brk);
 
         target_brk = brk_val;
         return target_brk;
     }
 
-    if (new_host_brk_page > brk_page) {
-        new_alloc_size = new_host_brk_page - brk_page;
-        mapped_addr = target_mmap(brk_page, new_alloc_size,
-                                  PROT_READ | PROT_WRITE,
-                                  MAP_FIXED_NOREPLACE | MAP_ANON | MAP_PRIVATE,
-                                  -1, 0);
-    } else {
-        new_alloc_size = 0;
-        mapped_addr = brk_page;
-    }
-
-    if (mapped_addr == brk_page) {
-        /* Heap contents are initialized to zero, as for anonymous
-         * mapped pages.  Technically the new pages are already
-         * initialized to zero since they *are* anonymous mapped
-         * pages, however we have to take care with the contents that
-         * come from the remaining part of the previous page: it may
-         * contains garbage data due to a previous heap usage (grown
-         * then shrunken).  */
-        memset(g2h_untagged(brk_page), 0, HOST_PAGE_ALIGN(brk_page) - brk_page);
+    mapped_addr = target_mmap(old_brk, new_brk - old_brk,
+                              PROT_READ | PROT_WRITE,
+                              MAP_FIXED_NOREPLACE | MAP_ANON | MAP_PRIVATE,
+                              -1, 0);
 
+    if (mapped_addr == old_brk) {
         target_brk = brk_val;
-        brk_page = new_host_brk_page;
         return target_brk;
     }
 
-- 
2.34.1

[PATCH v9 11/24] linux-user: Remove last_brk

[Richard Henderson]

This variable is unused.

Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/user-mmap.h | 1 -
 linux-user/mmap.c      | 2 --
 2 files changed, 3 deletions(-)

diff --git a/linux-user/user-mmap.h b/linux-user/user-mmap.h
index 3fc986f92f..7265c2c116 100644
--- a/linux-user/user-mmap.h
+++ b/linux-user/user-mmap.h
@@ -26,7 +26,6 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                        abi_ulong new_size, unsigned long flags,
                        abi_ulong new_addr);
 abi_long target_madvise(abi_ulong start, abi_ulong len_in, int advice);
-extern unsigned long last_brk;
 extern abi_ulong mmap_next_start;
 abi_ulong mmap_find_vma(abi_ulong, abi_ulong, abi_ulong);
 void mmap_fork_start(void);
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 90b3ef2140..eb04fab8ab 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -314,8 +314,6 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
 #endif
 abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
 
-unsigned long last_brk;
-
 /*
  * Subroutine of mmap_find_vma, used when we have pre-allocated
  * a chunk of guest address space.
-- 
2.34.1

[PATCH v9 12/24] bsd-user: Remove last_brk

[Richard Henderson]

This variable is unused.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/qemu.h | 1 -
 bsd-user/mmap.c | 2 --
 2 files changed, 3 deletions(-)

diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index edf9602f9b..8f2d6a3c78 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -232,7 +232,6 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                        abi_ulong new_size, unsigned long flags,
                        abi_ulong new_addr);
 int target_msync(abi_ulong start, abi_ulong len, int flags);
-extern unsigned long last_brk;
 extern abi_ulong mmap_next_start;
 abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size);
 void TSA_NO_TSA mmap_fork_start(void);
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index b62a69bd07..8e148a2ea3 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -214,8 +214,6 @@ static int mmap_frag(abi_ulong real_start,
 #endif
 abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
 
-unsigned long last_brk;
-
 /*
  * Subroutine of mmap_find_vma, used when we have pre-allocated a chunk of guest
  * address space.
-- 
2.34.1

[PATCH v9 13/24] linux-user: Adjust task_unmapped_base for reserved_va

[Richard Henderson]

Ensure that the chosen values for mmap_next_start and
task_unmapped_base are within the guest address space.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/user-mmap.h | 18 +++++++++++++++++-
 linux-user/main.c      | 28 ++++++++++++++++++++++++++++
 linux-user/mmap.c      | 18 +++---------------
 3 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/linux-user/user-mmap.h b/linux-user/user-mmap.h
index 7265c2c116..fd456e024e 100644
--- a/linux-user/user-mmap.h
+++ b/linux-user/user-mmap.h
@@ -18,6 +18,23 @@
 #ifndef LINUX_USER_USER_MMAP_H
 #define LINUX_USER_USER_MMAP_H
 
+#if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
+#ifdef TARGET_AARCH64
+# define TASK_UNMAPPED_BASE  0x5500000000
+#else
+# define TASK_UNMAPPED_BASE  (1ul << 38)
+#endif
+#else
+#ifdef TARGET_HPPA
+# define TASK_UNMAPPED_BASE  0xfa000000
+#else
+# define TASK_UNMAPPED_BASE  0x40000000
+#endif
+#endif
+
+extern abi_ulong task_unmapped_base;
+extern abi_ulong mmap_next_start;
+
 int target_mprotect(abi_ulong start, abi_ulong len, int prot);
 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                      int flags, int fd, off_t offset);
@@ -26,7 +43,6 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                        abi_ulong new_size, unsigned long flags,
                        abi_ulong new_addr);
 abi_long target_madvise(abi_ulong start, abi_ulong len_in, int advice);
-extern abi_ulong mmap_next_start;
 abi_ulong mmap_find_vma(abi_ulong, abi_ulong, abi_ulong);
 void mmap_fork_start(void);
 void mmap_fork_end(int child);
diff --git a/linux-user/main.c b/linux-user/main.c
index dba67ffa36..7ba7039988 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -821,6 +821,34 @@ int main(int argc, char **argv, char **envp)
         reserved_va = max_reserved_va;
     }
 
+    /*
+     * Temporarily disable
+     *   "comparison is always false due to limited range of data type"
+     * due to comparison between (possible) uint64_t and uintptr_t.
+     */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtype-limits"
+
+    /*
+     * Select an initial value for task_unmapped_base that is in range.
+     */
+    if (reserved_va) {
+        if (TASK_UNMAPPED_BASE < reserved_va) {
+            task_unmapped_base = TASK_UNMAPPED_BASE;
+        } else {
+            /* The most common default formula is TASK_SIZE / 3. */
+            task_unmapped_base = TARGET_PAGE_ALIGN(reserved_va / 3);
+        }
+    } else if (TASK_UNMAPPED_BASE < UINTPTR_MAX) {
+        task_unmapped_base = TASK_UNMAPPED_BASE;
+    } else {
+        /* 32-bit host: pick something medium size. */
+        task_unmapped_base = 0x10000000;
+    }
+    mmap_next_start = task_unmapped_base;
+
+#pragma GCC diagnostic pop
+
     {
         Error *err = NULL;
         if (seed_optarg != NULL) {
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index eb04fab8ab..84436d45c8 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -299,20 +299,8 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
     return true;
 }
 
-#if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
-#ifdef TARGET_AARCH64
-# define TASK_UNMAPPED_BASE  0x5500000000
-#else
-# define TASK_UNMAPPED_BASE  (1ul << 38)
-#endif
-#else
-#ifdef TARGET_HPPA
-# define TASK_UNMAPPED_BASE  0xfa000000
-#else
-# define TASK_UNMAPPED_BASE  0x40000000
-#endif
-#endif
-abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
+abi_ulong task_unmapped_base;
+abi_ulong mmap_next_start;
 
 /*
  * Subroutine of mmap_find_vma, used when we have pre-allocated
@@ -391,7 +379,7 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size, abi_ulong align)
 
             if ((addr & (align - 1)) == 0) {
                 /* Success.  */
-                if (start == mmap_next_start && addr >= TASK_UNMAPPED_BASE) {
+                if (start == mmap_next_start && addr >= task_unmapped_base) {
                     mmap_next_start = addr + size;
                 }
                 return addr;
-- 
2.34.1

[PATCH v9 14/24] linux-user: Define TASK_UNMAPPED_BASE in $guest/target_mman.h

[Richard Henderson]

Provide default values that are as close as possible to the
values used by the guest's kernel.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/target_mman.h     | 10 ++++++++++
 linux-user/alpha/target_mman.h       |  8 ++++++++
 linux-user/arm/target_mman.h         |  8 ++++++++
 linux-user/cris/target_mman.h        |  9 +++++++++
 linux-user/hexagon/target_mman.h     | 10 ++++++++++
 linux-user/hppa/target_mman.h        |  3 +++
 linux-user/i386/target_mman.h        | 13 +++++++++++++
 linux-user/loongarch64/target_mman.h |  8 ++++++++
 linux-user/m68k/target_mman.h        |  3 +++
 linux-user/microblaze/target_mman.h  |  8 ++++++++
 linux-user/mips/target_mman.h        |  7 +++++++
 linux-user/nios2/target_mman.h       |  7 +++++++
 linux-user/openrisc/target_mman.h    |  7 +++++++
 linux-user/ppc/target_mman.h         | 13 +++++++++++++
 linux-user/riscv/target_mman.h       |  7 +++++++
 linux-user/s390x/target_mman.h       | 10 ++++++++++
 linux-user/sh4/target_mman.h         |  4 ++++
 linux-user/sparc/target_mman.h       | 14 ++++++++++++++
 linux-user/user-mmap.h               | 14 --------------
 linux-user/x86_64/target_mman.h      | 12 ++++++++++++
 linux-user/xtensa/target_mman.h      |  6 ++++++
 21 files changed, 167 insertions(+), 14 deletions(-)

diff --git a/linux-user/aarch64/target_mman.h b/linux-user/aarch64/target_mman.h
index f721295fe1..4d3eecfb26 100644
--- a/linux-user/aarch64/target_mman.h
+++ b/linux-user/aarch64/target_mman.h
@@ -4,6 +4,16 @@
 #define TARGET_PROT_BTI         0x10
 #define TARGET_PROT_MTE         0x20
 
+/*
+ * arch/arm64/include/asm/processor.h:
+ *
+ * TASK_UNMAPPED_BASE     DEFAULT_MAP_WINDOW / 4
+ * DEFAULT_MAP_WINDOW     DEFAULT_MAP_WINDOW_64
+ * DEFAULT_MAP_WINDOW_64  UL(1) << VA_BITS_MIN
+ * VA_BITS_MIN            48 (unless explicitly configured smaller)
+ */
+#define TASK_UNMAPPED_BASE      (1ull << (48 - 2))
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/alpha/target_mman.h b/linux-user/alpha/target_mman.h
index 6bb03e7336..c90b493711 100644
--- a/linux-user/alpha/target_mman.h
+++ b/linux-user/alpha/target_mman.h
@@ -20,6 +20,14 @@
 #define TARGET_MS_SYNC 2
 #define TARGET_MS_INVALIDATE 4
 
+/*
+ * arch/alpha/include/asm/processor.h:
+ *
+ * TASK_UNMAPPED_BASE           TASK_SIZE / 2
+ * TASK_SIZE                    0x40000000000UL
+ */
+#define TASK_UNMAPPED_BASE      0x20000000000ull
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/arm/target_mman.h b/linux-user/arm/target_mman.h
index e7ba6070fe..76275b2c7e 100644
--- a/linux-user/arm/target_mman.h
+++ b/linux-user/arm/target_mman.h
@@ -1 +1,9 @@
+/*
+ * arch/arm/include/asm/memory.h
+ * TASK_UNMAPPED_BASE        ALIGN(TASK_SIZE / 3, SZ_16M)
+ * TASK_SIZE                 CONFIG_PAGE_OFFSET
+ * CONFIG_PAGE_OFFSET        0xC0000000 (default in Kconfig)
+ */
+#define TASK_UNMAPPED_BASE   0x40000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/cris/target_mman.h b/linux-user/cris/target_mman.h
index e7ba6070fe..9df7b1eda5 100644
--- a/linux-user/cris/target_mman.h
+++ b/linux-user/cris/target_mman.h
@@ -1 +1,10 @@
+/*
+ * arch/cris/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE / 3))
+ *
+ * arch/cris/include/arch-v32/arch/processor.h
+ * TASK_SIZE               0xb0000000
+ */
+#define TASK_UNMAPPED_BASE TARGET_PAGE_ALIGN(0xb0000000 / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/hexagon/target_mman.h b/linux-user/hexagon/target_mman.h
index e7ba6070fe..c5ae336e07 100644
--- a/linux-user/hexagon/target_mman.h
+++ b/linux-user/hexagon/target_mman.h
@@ -1 +1,11 @@
+/*
+ * arch/hexgon/include/asm/processor.h
+ * TASK_UNMAPPED_BASE        PAGE_ALIGN(TASK_SIZE / 3)
+ *
+ * arch/hexagon/include/asm/mem-layout.h
+ * TASK_SIZE                 PAGE_OFFSET
+ * PAGE_OFFSET               0xc0000000
+ */
+#define TASK_UNMAPPED_BASE   0x40000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/hppa/target_mman.h b/linux-user/hppa/target_mman.h
index 97f87d042a..6459e7dbdd 100644
--- a/linux-user/hppa/target_mman.h
+++ b/linux-user/hppa/target_mman.h
@@ -24,6 +24,9 @@
 #define TARGET_MS_ASYNC 2
 #define TARGET_MS_INVALIDATE 4
 
+/* arch/parisc/include/asm/processor.h: DEFAULT_MAP_BASE32 */
+#define TASK_UNMAPPED_BASE      0x40000000
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/i386/target_mman.h b/linux-user/i386/target_mman.h
index e7ba6070fe..cc3382007f 100644
--- a/linux-user/i386/target_mman.h
+++ b/linux-user/i386/target_mman.h
@@ -1 +1,14 @@
+/*
+ * arch/x86/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         __TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
+ * __TASK_UNMAPPED_BASE(S)    PAGE_ALIGN(S / 3)
+ *
+ * arch/x86/include/asm/page_32_types.h:
+ * TASK_SIZE_LOW              TASK_SIZE
+ * TASK_SIZE                  __PAGE_OFFSET
+ * __PAGE_OFFSET              CONFIG_PAGE_OFFSET
+ * CONFIG_PAGE_OFFSET         0xc0000000 (default in Kconfig)
+ */
+#define TASK_UNMAPPED_BASE    0x40000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/loongarch64/target_mman.h b/linux-user/loongarch64/target_mman.h
index e7ba6070fe..d70e44d44c 100644
--- a/linux-user/loongarch64/target_mman.h
+++ b/linux-user/loongarch64/target_mman.h
@@ -1 +1,9 @@
+/*
+ * arch/loongarch/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         PAGE_ALIGN(TASK_SIZE / 3)
+ * TASK_SIZE64                0x1UL << (... ? VA_BITS : ...)
+ */
+#define TASK_UNMAPPED_BASE \
+    TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/m68k/target_mman.h b/linux-user/m68k/target_mman.h
index e7ba6070fe..d3eceb663b 100644
--- a/linux-user/m68k/target_mman.h
+++ b/linux-user/m68k/target_mman.h
@@ -1 +1,4 @@
+/* arch/m68k/include/asm/processor.h */
+#define TASK_UNMAPPED_BASE      0xC0000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/microblaze/target_mman.h b/linux-user/microblaze/target_mman.h
index e7ba6070fe..ffee869db4 100644
--- a/linux-user/microblaze/target_mman.h
+++ b/linux-user/microblaze/target_mman.h
@@ -1 +1,9 @@
+/*
+ * arch/microblaze/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE           (TASK_SIZE / 8 * 3)
+ * TASK_SIZE                    CONFIG_KERNEL_START
+ * CONFIG_KERNEL_START          0xc0000000 (default in Kconfig)
+ */
+#define TASK_UNMAPPED_BASE      0x48000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/mips/target_mman.h b/linux-user/mips/target_mman.h
index e97694aa4e..fe1eec2d0b 100644
--- a/linux-user/mips/target_mman.h
+++ b/linux-user/mips/target_mman.h
@@ -14,6 +14,13 @@
 #define TARGET_MAP_STACK                0x40000
 #define TARGET_MAP_HUGETLB              0x80000
 
+/*
+ * arch/mips/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         PAGE_ALIGN(TASK_SIZE / 3)
+ */
+#define TASK_UNMAPPED_BASE \
+    TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/nios2/target_mman.h b/linux-user/nios2/target_mman.h
index e7ba6070fe..ce18f4f871 100644
--- a/linux-user/nios2/target_mman.h
+++ b/linux-user/nios2/target_mman.h
@@ -1 +1,8 @@
+/*
+ * arch/nios2/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         PAGE_ALIGN(TASK_SIZE / 3)
+ * TASK_SIZE                  0x7FFF0000UL
+ */
+#define TASK_UNMAPPED_BASE    TARGET_PAGE_ALIGN(0x7FFF0000 / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/openrisc/target_mman.h b/linux-user/openrisc/target_mman.h
index e7ba6070fe..f1aaad809d 100644
--- a/linux-user/openrisc/target_mman.h
+++ b/linux-user/openrisc/target_mman.h
@@ -1 +1,8 @@
+/*
+ * arch/openrisc/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE      (TASK_SIZE / 8 * 3)
+ * TASK_SIZE               (0x80000000UL)
+ */
+#define TASK_UNMAPPED_BASE      0x30000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/ppc/target_mman.h b/linux-user/ppc/target_mman.h
index 67cc218f2e..04f99c6077 100644
--- a/linux-user/ppc/target_mman.h
+++ b/linux-user/ppc/target_mman.h
@@ -4,6 +4,19 @@
 #define TARGET_MAP_NORESERVE            0x40
 #define TARGET_MAP_LOCKED               0x80
 
+/*
+ * arch/powerpc/include/asm/task_size_64.h
+ * TASK_UNMAPPED_BASE_USER32    (PAGE_ALIGN(TASK_SIZE_USER32 / 4))
+ * TASK_UNMAPPED_BASE_USER64    (PAGE_ALIGN(DEFAULT_MAP_WINDOW_USER64 / 4))
+ * TASK_SIZE_USER32             (0x0000000100000000UL - (1 * PAGE_SIZE))
+ * DEFAULT_MAP_WINDOW_USER64    TASK_SIZE_64TB (with 4k pages)
+ */
+#ifdef TARGET_PPC64
+#define TASK_UNMAPPED_BASE      0x0000100000000000ull
+#else
+#define TASK_UNMAPPED_BASE      0x40000000
+#endif
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/riscv/target_mman.h b/linux-user/riscv/target_mman.h
index e7ba6070fe..0f06dadbd4 100644
--- a/linux-user/riscv/target_mman.h
+++ b/linux-user/riscv/target_mman.h
@@ -1 +1,8 @@
+/*
+ * arch/loongarch/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         PAGE_ALIGN(TASK_SIZE / 3)
+ */
+#define TASK_UNMAPPED_BASE \
+    TARGET_PAGE_ALIGN((1ull << (TARGET_VIRT_ADDR_SPACE_BITS - 1)) / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/s390x/target_mman.h b/linux-user/s390x/target_mman.h
index e7ba6070fe..40d149b329 100644
--- a/linux-user/s390x/target_mman.h
+++ b/linux-user/s390x/target_mman.h
@@ -1 +1,11 @@
+/*
+ * arch/s390/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE           (... : (_REGION2_SIZE >> 1))
+ *
+ * arch/s390/include/asm/pgtable.h:
+ * _REGION2_SIZE                (1UL << _REGION2_SHIFT)
+ * _REGION2_SHIFT               42
+ */
+#define TASK_UNMAPPED_BASE      (1ull << 41)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/sh4/target_mman.h b/linux-user/sh4/target_mman.h
index e7ba6070fe..bbbc223398 100644
--- a/linux-user/sh4/target_mman.h
+++ b/linux-user/sh4/target_mman.h
@@ -1 +1,5 @@
+/* arch/sh/include/asm/processor_32.h */
+#define TASK_UNMAPPED_BASE \
+    TARGET_PAGE_ALIGN((1u << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/sparc/target_mman.h b/linux-user/sparc/target_mman.h
index 9bad99c852..692ebf9dd7 100644
--- a/linux-user/sparc/target_mman.h
+++ b/linux-user/sparc/target_mman.h
@@ -5,6 +5,20 @@
 #define TARGET_MAP_LOCKED              0x100
 #define TARGET_MAP_GROWSDOWN           0x0200
 
+/*
+ * arch/sparc/include/asm/page_64.h:
+ * TASK_UNMAPPED_BASE      (test_thread_flag(TIF_32BIT) ? \
+ *                          _AC(0x0000000070000000,UL) : \
+ *                          VA_EXCLUDE_END)
+ * But VA_EXCLUDE_END is > 0xffff800000000000UL which doesn't work
+ * in userland emulation.
+ */
+#ifdef TARGET_ABI32
+#define TASK_UNMAPPED_BASE      0x70000000
+#else
+#define TASK_UNMAPPED_BASE      (1ull << (TARGET_VIRT_ADDR_SPACE_BITS - 2))
+#endif
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/user-mmap.h b/linux-user/user-mmap.h
index fd456e024e..bae49059e0 100644
--- a/linux-user/user-mmap.h
+++ b/linux-user/user-mmap.h
@@ -18,20 +18,6 @@
 #ifndef LINUX_USER_USER_MMAP_H
 #define LINUX_USER_USER_MMAP_H
 
-#if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
-#ifdef TARGET_AARCH64
-# define TASK_UNMAPPED_BASE  0x5500000000
-#else
-# define TASK_UNMAPPED_BASE  (1ul << 38)
-#endif
-#else
-#ifdef TARGET_HPPA
-# define TASK_UNMAPPED_BASE  0xfa000000
-#else
-# define TASK_UNMAPPED_BASE  0x40000000
-#endif
-#endif
-
 extern abi_ulong task_unmapped_base;
 extern abi_ulong mmap_next_start;
 
diff --git a/linux-user/x86_64/target_mman.h b/linux-user/x86_64/target_mman.h
index e7ba6070fe..f9ff652b37 100644
--- a/linux-user/x86_64/target_mman.h
+++ b/linux-user/x86_64/target_mman.h
@@ -1 +1,13 @@
+/*
+ * arch/x86/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE         __TASK_UNMAPPED_BASE(TASK_SIZE_LOW)
+ * __TASK_UNMAPPED_BASE(S)    PAGE_ALIGN(S / 3)
+ *
+ * arch/x86/include/asm/page_64_types.h:
+ * TASK_SIZE_LOW              DEFAULT_MAP_WINDOW
+ * DEFAULT_MAP_WINDOW         ((1UL << 47) - PAGE_SIZE)
+ */
+#define TASK_UNMAPPED_BASE \
+    TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/xtensa/target_mman.h b/linux-user/xtensa/target_mman.h
index 3933771b5b..c4f671adb7 100644
--- a/linux-user/xtensa/target_mman.h
+++ b/linux-user/xtensa/target_mman.h
@@ -14,6 +14,12 @@
 #define TARGET_MAP_STACK                0x40000
 #define TARGET_MAP_HUGETLB              0x80000
 
+/*
+ * arch/xtensa/include/asm/processor.h:
+ * TASK_UNMAPPED_BASE           (TASK_SIZE / 2)
+ */
+#define TASK_UNMAPPED_BASE      (1u << (TARGET_VIRT_ADDR_SPACE_BITS - 1))
+
 #include "../generic/target_mman.h"
 
 #endif
-- 
2.34.1

[PATCH v9 15/24] linux-user: Define ELF_ET_DYN_BASE in $guest/target_mman.h

[Richard Henderson]

Copy each guest kernel's default value, then bound it
against reserved_va or the host address space.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/target_mman.h     |  3 +++
 linux-user/alpha/target_mman.h       |  3 +++
 linux-user/arm/target_mman.h         |  3 +++
 linux-user/cris/target_mman.h        |  3 +++
 linux-user/hexagon/target_mman.h     |  3 +++
 linux-user/hppa/target_mman.h        |  3 +++
 linux-user/i386/target_mman.h        |  3 +++
 linux-user/loongarch64/target_mman.h |  3 +++
 linux-user/m68k/target_mman.h        |  2 ++
 linux-user/microblaze/target_mman.h  |  3 +++
 linux-user/mips/target_mman.h        |  3 +++
 linux-user/nios2/target_mman.h       |  3 +++
 linux-user/openrisc/target_mman.h    |  3 +++
 linux-user/ppc/target_mman.h         |  7 +++++++
 linux-user/riscv/target_mman.h       |  3 +++
 linux-user/s390x/target_mman.h       | 10 ++++++++++
 linux-user/sh4/target_mman.h         |  3 +++
 linux-user/sparc/target_mman.h       | 11 +++++++++++
 linux-user/user-mmap.h               |  1 +
 linux-user/x86_64/target_mman.h      |  3 +++
 linux-user/xtensa/target_mman.h      |  4 ++++
 linux-user/main.c                    | 15 +++++++++++++++
 linux-user/mmap.c                    |  1 +
 23 files changed, 96 insertions(+)

diff --git a/linux-user/aarch64/target_mman.h b/linux-user/aarch64/target_mman.h
index 4d3eecfb26..69ec5d5739 100644
--- a/linux-user/aarch64/target_mman.h
+++ b/linux-user/aarch64/target_mman.h
@@ -14,6 +14,9 @@
  */
 #define TASK_UNMAPPED_BASE      (1ull << (48 - 2))
 
+/* arch/arm64/include/asm/elf.h */
+#define ELF_ET_DYN_BASE         TARGET_PAGE_ALIGN((1ull << 48) / 3 * 2)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/alpha/target_mman.h b/linux-user/alpha/target_mman.h
index c90b493711..8edfe2b88c 100644
--- a/linux-user/alpha/target_mman.h
+++ b/linux-user/alpha/target_mman.h
@@ -28,6 +28,9 @@
  */
 #define TASK_UNMAPPED_BASE      0x20000000000ull
 
+/* arch/alpha/include/asm/elf.h */
+#define ELF_ET_DYN_BASE         (TASK_UNMAPPED_BASE + 0x1000000)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/arm/target_mman.h b/linux-user/arm/target_mman.h
index 76275b2c7e..51005da869 100644
--- a/linux-user/arm/target_mman.h
+++ b/linux-user/arm/target_mman.h
@@ -6,4 +6,7 @@
  */
 #define TASK_UNMAPPED_BASE   0x40000000
 
+/* arch/arm/include/asm/elf.h */
+#define ELF_ET_DYN_BASE      0x00400000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/cris/target_mman.h b/linux-user/cris/target_mman.h
index 9df7b1eda5..9ace8ac292 100644
--- a/linux-user/cris/target_mman.h
+++ b/linux-user/cris/target_mman.h
@@ -7,4 +7,7 @@
  */
 #define TASK_UNMAPPED_BASE TARGET_PAGE_ALIGN(0xb0000000 / 3)
 
+/* arch/cris/include/uapi/asm/elf.h */
+#define ELF_ET_DYN_BASE    (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/hexagon/target_mman.h b/linux-user/hexagon/target_mman.h
index c5ae336e07..e6b5e2ca36 100644
--- a/linux-user/hexagon/target_mman.h
+++ b/linux-user/hexagon/target_mman.h
@@ -8,4 +8,7 @@
  */
 #define TASK_UNMAPPED_BASE   0x40000000
 
+/* arch/hexagon/include/asm/elf.h */
+#define ELF_ET_DYN_BASE      0x08000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/hppa/target_mman.h b/linux-user/hppa/target_mman.h
index 6459e7dbdd..ccda46e842 100644
--- a/linux-user/hppa/target_mman.h
+++ b/linux-user/hppa/target_mman.h
@@ -27,6 +27,9 @@
 /* arch/parisc/include/asm/processor.h: DEFAULT_MAP_BASE32 */
 #define TASK_UNMAPPED_BASE      0x40000000
 
+/* arch/parisc/include/asm/elf.h */
+#define ELF_ET_DYN_BASE         (TASK_UNMAPPED_BASE + 0x01000000)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/i386/target_mman.h b/linux-user/i386/target_mman.h
index cc3382007f..e3b8e1eaa6 100644
--- a/linux-user/i386/target_mman.h
+++ b/linux-user/i386/target_mman.h
@@ -11,4 +11,7 @@
  */
 #define TASK_UNMAPPED_BASE    0x40000000
 
+/* arch/x86/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       0x00400000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/loongarch64/target_mman.h b/linux-user/loongarch64/target_mman.h
index d70e44d44c..8c2a3d5596 100644
--- a/linux-user/loongarch64/target_mman.h
+++ b/linux-user/loongarch64/target_mman.h
@@ -6,4 +6,7 @@
 #define TASK_UNMAPPED_BASE \
     TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
 
+/* arch/loongarch/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/m68k/target_mman.h b/linux-user/m68k/target_mman.h
index d3eceb663b..20cfe750c5 100644
--- a/linux-user/m68k/target_mman.h
+++ b/linux-user/m68k/target_mman.h
@@ -1,4 +1,6 @@
 /* arch/m68k/include/asm/processor.h */
 #define TASK_UNMAPPED_BASE      0xC0000000
+/* arch/m68k/include/asm/elf.h */
+#define ELF_ET_DYN_BASE         0xD0000000
 
 #include "../generic/target_mman.h"
diff --git a/linux-user/microblaze/target_mman.h b/linux-user/microblaze/target_mman.h
index ffee869db4..6b3dd54f89 100644
--- a/linux-user/microblaze/target_mman.h
+++ b/linux-user/microblaze/target_mman.h
@@ -6,4 +6,7 @@
  */
 #define TASK_UNMAPPED_BASE      0x48000000
 
+/* arch/microblaze/include/uapi/asm/elf.h */
+#define ELF_ET_DYN_BASE         0x08000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/mips/target_mman.h b/linux-user/mips/target_mman.h
index fe1eec2d0b..b84fe1e8a8 100644
--- a/linux-user/mips/target_mman.h
+++ b/linux-user/mips/target_mman.h
@@ -21,6 +21,9 @@
 #define TASK_UNMAPPED_BASE \
     TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
 
+/* arch/mips/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/nios2/target_mman.h b/linux-user/nios2/target_mman.h
index ce18f4f871..ab16ad4f03 100644
--- a/linux-user/nios2/target_mman.h
+++ b/linux-user/nios2/target_mman.h
@@ -5,4 +5,7 @@
  */
 #define TASK_UNMAPPED_BASE    TARGET_PAGE_ALIGN(0x7FFF0000 / 3)
 
+/* arch/nios2/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       0xD0000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/openrisc/target_mman.h b/linux-user/openrisc/target_mman.h
index f1aaad809d..243c1d5f26 100644
--- a/linux-user/openrisc/target_mman.h
+++ b/linux-user/openrisc/target_mman.h
@@ -5,4 +5,7 @@
  */
 #define TASK_UNMAPPED_BASE      0x30000000
 
+/* arch/openrisc/include/asm/elf.h */
+#define ELF_ET_DYN_BASE         0x08000000
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/ppc/target_mman.h b/linux-user/ppc/target_mman.h
index 04f99c6077..646d1ccae7 100644
--- a/linux-user/ppc/target_mman.h
+++ b/linux-user/ppc/target_mman.h
@@ -17,6 +17,13 @@
 #define TASK_UNMAPPED_BASE      0x40000000
 #endif
 
+/* arch/powerpc/include/asm/elf.h */
+#ifdef TARGET_PPC64
+#define ELF_ET_DYN_BASE         0x100000000ull
+#else
+#define ELF_ET_DYN_BASE         0x000400000
+#endif
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/riscv/target_mman.h b/linux-user/riscv/target_mman.h
index 0f06dadbd4..3049bcc67d 100644
--- a/linux-user/riscv/target_mman.h
+++ b/linux-user/riscv/target_mman.h
@@ -5,4 +5,7 @@
 #define TASK_UNMAPPED_BASE \
     TARGET_PAGE_ALIGN((1ull << (TARGET_VIRT_ADDR_SPACE_BITS - 1)) / 3)
 
+/* arch/riscv/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/s390x/target_mman.h b/linux-user/s390x/target_mman.h
index 40d149b329..c82435e381 100644
--- a/linux-user/s390x/target_mman.h
+++ b/linux-user/s390x/target_mman.h
@@ -8,4 +8,14 @@
  */
 #define TASK_UNMAPPED_BASE      (1ull << 41)
 
+/*
+ * arch/s390/include/asm/elf.h:
+ * ELF_ET_DYN_BASE              (STACK_TOP / 3 * 2) & ~((1UL << 32) - 1)
+ *
+ * arch/s390/include/asm/processor.h:
+ * STACK_TOP                    VDSO_LIMIT - VDSO_SIZE - PAGE_SIZE
+ * VDSO_LIMIT                   _REGION2_SIZE
+ */
+#define ELF_ET_DYN_BASE         (((1ull << 42) / 3 * 2) & ~0xffffffffull)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/sh4/target_mman.h b/linux-user/sh4/target_mman.h
index bbbc223398..dd9016081e 100644
--- a/linux-user/sh4/target_mman.h
+++ b/linux-user/sh4/target_mman.h
@@ -2,4 +2,7 @@
 #define TASK_UNMAPPED_BASE \
     TARGET_PAGE_ALIGN((1u << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
 
+/* arch/sh/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/sparc/target_mman.h b/linux-user/sparc/target_mman.h
index 692ebf9dd7..696ca73fe4 100644
--- a/linux-user/sparc/target_mman.h
+++ b/linux-user/sparc/target_mman.h
@@ -19,6 +19,17 @@
 #define TASK_UNMAPPED_BASE      (1ull << (TARGET_VIRT_ADDR_SPACE_BITS - 2))
 #endif
 
+/*
+ * arch/sparc/include/asm/elf_64.h
+ * Except that COMPAT_ELF_ET_DYN_BASE exactly matches TASK_UNMAPPED_BASE,
+ * so move it up a bit.
+ */
+#ifdef TARGET_ABI32
+#define ELF_ET_DYN_BASE         0x78000000
+#else
+#define ELF_ET_DYN_BASE         0x0000010000000000ull
+#endif
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/user-mmap.h b/linux-user/user-mmap.h
index bae49059e0..5dd48a458d 100644
--- a/linux-user/user-mmap.h
+++ b/linux-user/user-mmap.h
@@ -20,6 +20,7 @@
 
 extern abi_ulong task_unmapped_base;
 extern abi_ulong mmap_next_start;
+extern abi_ulong elf_et_dyn_base;
 
 int target_mprotect(abi_ulong start, abi_ulong len, int prot);
 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
diff --git a/linux-user/x86_64/target_mman.h b/linux-user/x86_64/target_mman.h
index f9ff652b37..48fbf20b42 100644
--- a/linux-user/x86_64/target_mman.h
+++ b/linux-user/x86_64/target_mman.h
@@ -10,4 +10,7 @@
 #define TASK_UNMAPPED_BASE \
     TARGET_PAGE_ALIGN((1ull << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
 
+/* arch/x86/include/asm/elf.h */
+#define ELF_ET_DYN_BASE       (TASK_UNMAPPED_BASE * 2)
+
 #include "../generic/target_mman.h"
diff --git a/linux-user/xtensa/target_mman.h b/linux-user/xtensa/target_mman.h
index c4f671adb7..8fa6337a97 100644
--- a/linux-user/xtensa/target_mman.h
+++ b/linux-user/xtensa/target_mman.h
@@ -20,6 +20,10 @@
  */
 #define TASK_UNMAPPED_BASE      (1u << (TARGET_VIRT_ADDR_SPACE_BITS - 1))
 
+/* arch/xtensa/include/asm/elf.h */
+#define ELF_ET_DYN_BASE \
+    TARGET_PAGE_ALIGN((1u << TARGET_VIRT_ADDR_SPACE_BITS) / 3)
+
 #include "../generic/target_mman.h"
 
 #endif
diff --git a/linux-user/main.c b/linux-user/main.c
index 7ba7039988..cb5e80612b 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -847,6 +847,21 @@ int main(int argc, char **argv, char **envp)
     }
     mmap_next_start = task_unmapped_base;
 
+    /* Similarly for elf_et_dyn_base. */
+    if (reserved_va) {
+        if (ELF_ET_DYN_BASE < reserved_va) {
+            elf_et_dyn_base = ELF_ET_DYN_BASE;
+        } else {
+            /* The most common default formula is TASK_SIZE / 3 * 2. */
+            elf_et_dyn_base = TARGET_PAGE_ALIGN(reserved_va / 3) * 2;
+        }
+    } else if (ELF_ET_DYN_BASE < UINTPTR_MAX) {
+        elf_et_dyn_base = ELF_ET_DYN_BASE;
+    } else {
+        /* 32-bit host: pick something medium size. */
+        elf_et_dyn_base = 0x18000000;
+    }
+
 #pragma GCC diagnostic pop
 
     {
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 84436d45c8..949c4090f3 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -301,6 +301,7 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
 
 abi_ulong task_unmapped_base;
 abi_ulong mmap_next_start;
+abi_ulong elf_et_dyn_base;
 
 /*
  * Subroutine of mmap_find_vma, used when we have pre-allocated
-- 
2.34.1

[PATCH v9 16/24] linux-user: Use MAP_FIXED_NOREPLACE for initial image mmap

[Richard Henderson]

Use this as extra protection for the guest mapping over
any qemu host mappings.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 2aee2298ec..0c64aad8a5 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3146,8 +3146,11 @@ static void load_elf_image(const char *image_name, int image_fd,
     /*
      * Reserve address space for all of this.
      *
-     * In the case of ET_EXEC, we supply MAP_FIXED so that we get
-     * exactly the address range that is required.
+     * In the case of ET_EXEC, we supply MAP_FIXED_NOREPLACE so that we get
+     * exactly the address range that is required.  Without reserved_va,
+     * the guest address space is not isolated.  We have attempted to avoid
+     * conflict with the host program itself via probe_guest_base, but using
+     * MAP_FIXED_NOREPLACE instead of MAP_FIXED provides an extra check.
      *
      * Otherwise this is ET_DYN, and we are searching for a location
      * that can hold the memory space required.  If the image is
@@ -3159,7 +3162,7 @@ static void load_elf_image(const char *image_name, int image_fd,
      */
     load_addr = target_mmap(loaddr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
                             MAP_PRIVATE | MAP_ANON | MAP_NORESERVE |
-                            (ehdr->e_type == ET_EXEC ? MAP_FIXED : 0),
+                            (ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE : 0),
                             -1, 0);
     if (load_addr == -1) {
         goto exit_mmap;
-- 
2.34.1

[PATCH v9 17/24] linux-user: Use elf_et_dyn_base for ET_DYN with interpreter

[Richard Henderson]

Follow the lead of the linux kernel in fs/binfmt_elf.c,
in which an ET_DYN executable which uses an interpreter
(usually a PIE executable) is loaded away from where the
interpreter itself will be loaded.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 0c64aad8a5..a3aa08a13e 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3106,6 +3106,8 @@ static void load_elf_image(const char *image_name, int image_fd,
         }
     }
 
+    load_addr = loaddr;
+
     if (pinterp_name != NULL) {
         /*
          * This is the main executable.
@@ -3135,11 +3137,32 @@ static void load_elf_image(const char *image_name, int image_fd,
              */
             probe_guest_base(image_name, loaddr, hiaddr);
         } else {
+            abi_ulong align;
+
             /*
              * The binary is dynamic, but we still need to
              * select guest_base.  In this case we pass a size.
              */
             probe_guest_base(image_name, 0, hiaddr - loaddr);
+
+            /*
+             * Avoid collision with the loader by providing a different
+             * default load address.
+             */
+            load_addr += elf_et_dyn_base;
+
+            /*
+             * TODO: Better support for mmap alignment is desirable.
+             * Since we do not have complete control over the guest
+             * address space, we prefer the kernel to choose some address
+             * rather than force the use of LOAD_ADDR via MAP_FIXED.
+             * But without MAP_FIXED we cannot guarantee alignment,
+             * only suggest it.
+             */
+            align = pow2ceil(info->alignment);
+            if (align) {
+                load_addr &= -align;
+            }
         }
     }
 
@@ -3154,13 +3177,13 @@ static void load_elf_image(const char *image_name, int image_fd,
      *
      * Otherwise this is ET_DYN, and we are searching for a location
      * that can hold the memory space required.  If the image is
-     * pre-linked, LOADDR will be non-zero, and the kernel should
+     * pre-linked, LOAD_ADDR will be non-zero, and the kernel should
      * honor that address if it happens to be free.
      *
      * In both cases, we will overwrite pages in this range with mappings
      * from the executable.
      */
-    load_addr = target_mmap(loaddr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
+    load_addr = target_mmap(load_addr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
                             MAP_PRIVATE | MAP_ANON | MAP_NORESERVE |
                             (ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE : 0),
                             -1, 0);
-- 
2.34.1

[PATCH v9 18/24] linux-user: Adjust initial brk when interpreter is close to executable

[Richard Henderson]

From: Helge Deller <deller@gmx.de>

While we attempt to load a ET_DYN executable far away from
TASK_UNMAPPED_BASE, we are not completely in control of the
address space layout.  If the interpreter lands close to
the executable, leaving insufficient heap space, move brk.

Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
[rth: Re-order after ELF_ET_DYN_BASE patch so that we do not
 "temporarily break" tsan, and also to minimize the changes required.
 Remove image_info.reserve_brk as unused.]
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/qemu.h    |  1 -
 linux-user/elfload.c | 51 +++++++++++++-------------------------------
 2 files changed, 15 insertions(+), 37 deletions(-)

diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 802794db63..4b0c9da0dc 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -31,7 +31,6 @@ struct image_info {
         abi_ulong       end_data;
         abi_ulong       start_brk;
         abi_ulong       brk;
-        abi_ulong       reserve_brk;
         abi_ulong       start_mmap;
         abi_ulong       start_stack;
         abi_ulong       stack_limit;
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index a3aa08a13e..fa0c9ace8e 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3109,27 +3109,6 @@ static void load_elf_image(const char *image_name, int image_fd,
     load_addr = loaddr;
 
     if (pinterp_name != NULL) {
-        /*
-         * This is the main executable.
-         *
-         * Reserve extra space for brk.
-         * We hold on to this space while placing the interpreter
-         * and the stack, lest they be placed immediately after
-         * the data segment and block allocation from the brk.
-         *
-         * 16MB is chosen as "large enough" without being so large as
-         * to allow the result to not fit with a 32-bit guest on a
-         * 32-bit host. However some 64 bit guests (e.g. s390x)
-         * attempt to place their heap further ahead and currently
-         * nothing stops them smashing into QEMUs address space.
-         */
-#if TARGET_LONG_BITS == 64
-        info->reserve_brk = 32 * MiB;
-#else
-        info->reserve_brk = 16 * MiB;
-#endif
-        hiaddr += info->reserve_brk;
-
         if (ehdr->e_type == ET_EXEC) {
             /*
              * Make sure that the low address does not conflict with
@@ -3220,7 +3199,8 @@ static void load_elf_image(const char *image_name, int image_fd,
     info->end_code = 0;
     info->start_data = -1;
     info->end_data = 0;
-    info->brk = 0;
+    /* Usual start for brk is after all sections of the main executable. */
+    info->brk = TARGET_PAGE_ALIGN(hiaddr);
     info->elf_flags = ehdr->e_flags;
 
     prot_exec = PROT_EXEC;
@@ -3314,9 +3294,6 @@ static void load_elf_image(const char *image_name, int image_fd,
                     info->end_data = vaddr_ef;
                 }
             }
-            if (vaddr_em > info->brk) {
-                info->brk = vaddr_em;
-            }
 #ifdef TARGET_MIPS
         } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {
             Mips_elf_abiflags_v0 abiflags;
@@ -3645,6 +3622,19 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
     if (elf_interpreter) {
         load_elf_interp(elf_interpreter, &interp_info, bprm->buf);
 
+        /*
+         * While unusual because of ELF_ET_DYN_BASE, if we are unlucky
+         * with the mappings the interpreter can be loaded above but
+         * near the main executable, which can leave very little room
+         * for the heap.
+         * If the current brk has less than 16MB, use the end of the
+         * interpreter.
+         */
+        if (interp_info.brk > info->brk &&
+            interp_info.load_bias - info->brk < 16 * MiB)  {
+            info->brk = interp_info.brk;
+        }
+
         /* If the program interpreter is one of these two, then assume
            an iBCS2 image.  Otherwise assume a native linux image.  */
 
@@ -3698,17 +3688,6 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
     bprm->core_dump = &elf_core_dump;
 #endif
 
-    /*
-     * If we reserved extra space for brk, release it now.
-     * The implementation of do_brk in syscalls.c expects to be able
-     * to mmap pages in this space.
-     */
-    if (info->reserve_brk) {
-        abi_ulong start_brk = TARGET_PAGE_ALIGN(info->brk);
-        abi_ulong end_brk = TARGET_PAGE_ALIGN(info->brk + info->reserve_brk);
-        target_munmap(start_brk, end_brk - start_brk);
-    }
-
     return 0;
 }
 
-- 
2.34.1

[PATCH v9 19/24] linux-user: Properly set image_info.brk in flatload

[Richard Henderson]

The heap starts at "brk" not "start_brk".  With this fixed,
image_info.start_brk is unused and may be removed.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/qemu.h     | 1 -
 linux-user/flatload.c | 2 +-
 linux-user/main.c     | 2 --
 3 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 4b0c9da0dc..4f8b55e2fb 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -29,7 +29,6 @@ struct image_info {
         abi_ulong       end_code;
         abi_ulong       start_data;
         abi_ulong       end_data;
-        abi_ulong       start_brk;
         abi_ulong       brk;
         abi_ulong       start_mmap;
         abi_ulong       start_stack;
diff --git a/linux-user/flatload.c b/linux-user/flatload.c
index 5efec2630e..8f5e9f489b 100644
--- a/linux-user/flatload.c
+++ b/linux-user/flatload.c
@@ -811,7 +811,7 @@ int load_flt_binary(struct linux_binprm *bprm, struct image_info *info)
     info->end_code = libinfo[0].start_code + libinfo[0].text_len;
     info->start_data = libinfo[0].start_data;
     info->end_data = libinfo[0].end_data;
-    info->start_brk = libinfo[0].start_brk;
+    info->brk = libinfo[0].start_brk;
     info->start_stack = sp;
     info->stack_limit = libinfo[0].start_brk;
     info->entry = start_addr;
diff --git a/linux-user/main.c b/linux-user/main.c
index cb5e80612b..96be354897 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -963,8 +963,6 @@ int main(int argc, char **argv, char **envp)
             fprintf(f, "page layout changed following binary load\n");
             page_dump(f);
 
-            fprintf(f, "start_brk   0x" TARGET_ABI_FMT_lx "\n",
-                    info->start_brk);
             fprintf(f, "end_code    0x" TARGET_ABI_FMT_lx "\n",
                     info->end_code);
             fprintf(f, "start_code  0x" TARGET_ABI_FMT_lx "\n",
-- 
2.34.1

[PATCH v9 20/24] linux-user: Do not adjust image mapping for host page size

[Richard Henderson]

Remove TARGET_ELF_EXEC_PAGESIZE, and 3 other TARGET_ELF_PAGE* macros
based off of that.  Rely on target_mmap to handle guest vs host page
size mismatch.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index fa0c9ace8e..e853a4ab33 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1959,15 +1959,6 @@ struct exec
 #define ZMAGIC 0413
 #define QMAGIC 0314
 
-/* Necessary parameters */
-#define TARGET_ELF_EXEC_PAGESIZE \
-        (((eppnt->p_align & ~qemu_host_page_mask) != 0) ? \
-         TARGET_PAGE_SIZE : MAX(qemu_host_page_size, TARGET_PAGE_SIZE))
-#define TARGET_ELF_PAGELENGTH(_v) ROUND_UP((_v), TARGET_ELF_EXEC_PAGESIZE)
-#define TARGET_ELF_PAGESTART(_v) ((_v) & \
-                                 ~(abi_ulong)(TARGET_ELF_EXEC_PAGESIZE-1))
-#define TARGET_ELF_PAGEOFFSET(_v) ((_v) & (TARGET_ELF_EXEC_PAGESIZE-1))
-
 #define DLINFO_ITEMS 16
 
 static inline void memcpy_fromfs(void * to, const void * from, unsigned long n)
@@ -3240,8 +3231,8 @@ static void load_elf_image(const char *image_name, int image_fd,
             }
 
             vaddr = load_bias + eppnt->p_vaddr;
-            vaddr_po = TARGET_ELF_PAGEOFFSET(vaddr);
-            vaddr_ps = TARGET_ELF_PAGESTART(vaddr);
+            vaddr_po = vaddr & ~TARGET_PAGE_MASK;
+            vaddr_ps = vaddr & TARGET_PAGE_MASK;
 
             vaddr_ef = vaddr + eppnt->p_filesz;
             vaddr_em = vaddr + eppnt->p_memsz;
@@ -3251,7 +3242,7 @@ static void load_elf_image(const char *image_name, int image_fd,
              * but no backing file segment.
              */
             if (eppnt->p_filesz != 0) {
-                vaddr_len = TARGET_ELF_PAGELENGTH(eppnt->p_filesz + vaddr_po);
+                vaddr_len = eppnt->p_filesz + vaddr_po;
                 error = target_mmap(vaddr_ps, vaddr_len, elf_prot,
                                     MAP_PRIVATE | MAP_FIXED,
                                     image_fd, eppnt->p_offset - vaddr_po);
@@ -3267,7 +3258,7 @@ static void load_elf_image(const char *image_name, int image_fd,
                     zero_bss(vaddr_ef, vaddr_em, elf_prot);
                 }
             } else if (eppnt->p_memsz != 0) {
-                vaddr_len = TARGET_ELF_PAGELENGTH(eppnt->p_memsz + vaddr_po);
+                vaddr_len = eppnt->p_memsz + vaddr_po;
                 error = target_mmap(vaddr_ps, vaddr_len, elf_prot,
                                     MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
                                     -1, 0);
-- 
2.34.1

[PATCH v9 21/24] linux-user: Do not adjust zero_bss for host page size

[Richard Henderson]

Rely on target_mmap to handle guest vs host page size mismatch.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 54 +++++++++++++++++++-------------------------
 1 file changed, 23 insertions(+), 31 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index e853a4ab33..66ab617bd1 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2212,44 +2212,36 @@ static abi_ulong setup_arg_pages(struct linux_binprm *bprm,
 
 /* Map and zero the bss.  We need to explicitly zero any fractional pages
    after the data section (i.e. bss).  */
-static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot)
+static void zero_bss(abi_ulong start_bss, abi_ulong end_bss, int prot)
 {
-    uintptr_t host_start, host_map_start, host_end;
+    abi_ulong align_bss;
 
-    last_bss = TARGET_PAGE_ALIGN(last_bss);
+    align_bss = TARGET_PAGE_ALIGN(start_bss);
+    end_bss = TARGET_PAGE_ALIGN(end_bss);
 
-    /* ??? There is confusion between qemu_real_host_page_size and
-       qemu_host_page_size here and elsewhere in target_mmap, which
-       may lead to the end of the data section mapping from the file
-       not being mapped.  At least there was an explicit test and
-       comment for that here, suggesting that "the file size must
-       be known".  The comment probably pre-dates the introduction
-       of the fstat system call in target_mmap which does in fact
-       find out the size.  What isn't clear is if the workaround
-       here is still actually needed.  For now, continue with it,
-       but merge it with the "normal" mmap that would allocate the bss.  */
+    if (start_bss < align_bss) {
+        int flags = page_get_flags(start_bss);
 
-    host_start = (uintptr_t) g2h_untagged(elf_bss);
-    host_end = (uintptr_t) g2h_untagged(last_bss);
-    host_map_start = REAL_HOST_PAGE_ALIGN(host_start);
-
-    if (host_map_start < host_end) {
-        void *p = mmap((void *)host_map_start, host_end - host_map_start,
-                       prot, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-        if (p == MAP_FAILED) {
-            perror("cannot mmap brk");
-            exit(-1);
+        if (!(flags & PAGE_VALID)) {
+            /* Map the start of the bss. */
+            align_bss -= TARGET_PAGE_SIZE;
+        } else if (flags & PAGE_WRITE) {
+            /* The page is already mapped writable. */
+            memset(g2h_untagged(start_bss), 0, align_bss - start_bss);
+        } else {
+            /* Read-only zeros? */
+            g_assert_not_reached();
         }
     }
 
-    /* Ensure that the bss page(s) are valid */
-    if ((page_get_flags(last_bss-1) & prot) != prot) {
-        page_set_flags(elf_bss & TARGET_PAGE_MASK, last_bss - 1,
-                       prot | PAGE_VALID);
-    }
-
-    if (host_start < host_map_start) {
-        memset((void *)host_start, 0, host_map_start - host_start);
+    if (align_bss < end_bss) {
+        abi_long err = target_mmap(align_bss, end_bss - align_bss, prot,
+                                   MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
+                                   -1, 0);
+        if (err == -1) {
+            perror("cannot mmap brk");
+            exit(-1);
+        }
     }
 }
 
-- 
2.34.1

[PATCH v9 22/24] linux-user: Use zero_bss for PT_LOAD with no file contents too

[Richard Henderson]

If p_filesz == 0, then vaddr_ef == vaddr.  We can reuse the
code in zero_bss rather than incompletely duplicating it in
load_elf_image.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 66ab617bd1..51591a1d94 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -3209,7 +3209,7 @@ static void load_elf_image(const char *image_name, int image_fd,
     for (i = 0; i < ehdr->e_phnum; i++) {
         struct elf_phdr *eppnt = phdr + i;
         if (eppnt->p_type == PT_LOAD) {
-            abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em, vaddr_len;
+            abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em;
             int elf_prot = 0;
 
             if (eppnt->p_flags & PF_R) {
@@ -3234,30 +3234,17 @@ static void load_elf_image(const char *image_name, int image_fd,
              * but no backing file segment.
              */
             if (eppnt->p_filesz != 0) {
-                vaddr_len = eppnt->p_filesz + vaddr_po;
-                error = target_mmap(vaddr_ps, vaddr_len, elf_prot,
-                                    MAP_PRIVATE | MAP_FIXED,
+                error = target_mmap(vaddr_ps, eppnt->p_filesz + vaddr_po,
+                                    elf_prot, MAP_PRIVATE | MAP_FIXED,
                                     image_fd, eppnt->p_offset - vaddr_po);
-
                 if (error == -1) {
                     goto exit_mmap;
                 }
+            }
 
-                /*
-                 * If the load segment requests extra zeros (e.g. bss), map it.
-                 */
-                if (eppnt->p_filesz < eppnt->p_memsz) {
-                    zero_bss(vaddr_ef, vaddr_em, elf_prot);
-                }
-            } else if (eppnt->p_memsz != 0) {
-                vaddr_len = eppnt->p_memsz + vaddr_po;
-                error = target_mmap(vaddr_ps, vaddr_len, elf_prot,
-                                    MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
-                                    -1, 0);
-
-                if (error == -1) {
-                    goto exit_mmap;
-                }
+            /* If the load segment requests extra zeros (e.g. bss), map it. */
+            if (vaddr_ef < vaddr_em) {
+                zero_bss(vaddr_ef, vaddr_em, elf_prot);
             }
 
             /* Find the full program boundaries.  */
-- 
2.34.1

[PATCH v9 23/24] accel/tcg: Call save_iotlb_data from io_readx as well.

[Richard Henderson]

From: Mikhail Tyutin <m.tyutin@yadro.com>

Apply save_iotlb_data() to io_readx() as well as to io_writex().
This fixes SEGFAULT on qemu_plugin_hwaddr_phys_addr() call plugins
for addresses inside of MMIO region.

Signed-off-by: Dmitriy Solovev <d.solovev@yadro.com>
Signed-off-by: Mikhail Tyutin <m.tyutin@yadro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230804110903.19968-1-m.tyutin@yadro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 4b1bfaa53d..d68fa6867c 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1363,6 +1363,21 @@ static inline void cpu_transaction_failed(CPUState *cpu, hwaddr physaddr,
     }
 }
 
+/*
+ * Save a potentially trashed CPUTLBEntryFull for later lookup by plugin.
+ * This is read by tlb_plugin_lookup if the fulltlb entry doesn't match
+ * because of the side effect of io_writex changing memory layout.
+ */
+static void save_iotlb_data(CPUState *cs, MemoryRegionSection *section,
+                            hwaddr mr_offset)
+{
+#ifdef CONFIG_PLUGIN
+    SavedIOTLB *saved = &cs->saved_iotlb;
+    saved->section = section;
+    saved->mr_offset = mr_offset;
+#endif
+}
+
 static uint64_t io_readx(CPUArchState *env, CPUTLBEntryFull *full,
                          int mmu_idx, vaddr addr, uintptr_t retaddr,
                          MMUAccessType access_type, MemOp op)
@@ -1382,6 +1397,12 @@ static uint64_t io_readx(CPUArchState *env, CPUTLBEntryFull *full,
         cpu_io_recompile(cpu, retaddr);
     }
 
+    /*
+     * The memory_region_dispatch may trigger a flush/resize
+     * so for plugins we save the iotlb_data just in case.
+     */
+    save_iotlb_data(cpu, section, mr_offset);
+
     {
         QEMU_IOTHREAD_LOCK_GUARD();
         r = memory_region_dispatch_read(mr, mr_offset, &val, op, full->attrs);
@@ -1398,21 +1419,6 @@ static uint64_t io_readx(CPUArchState *env, CPUTLBEntryFull *full,
     return val;
 }
 
-/*
- * Save a potentially trashed CPUTLBEntryFull for later lookup by plugin.
- * This is read by tlb_plugin_lookup if the fulltlb entry doesn't match
- * because of the side effect of io_writex changing memory layout.
- */
-static void save_iotlb_data(CPUState *cs, MemoryRegionSection *section,
-                            hwaddr mr_offset)
-{
-#ifdef CONFIG_PLUGIN
-    SavedIOTLB *saved = &cs->saved_iotlb;
-    saved->section = section;
-    saved->mr_offset = mr_offset;
-#endif
-}
-
 static void io_writex(CPUArchState *env, CPUTLBEntryFull *full,
                       int mmu_idx, uint64_t val, vaddr addr,
                       uintptr_t retaddr, MemOp op)
-- 
2.34.1

[PATCH v9 24/24] linux-user/elfload: Set V in ELF_HWCAP for RISC-V

[Richard Henderson]

From: Nathan Egge <negge@xiph.org>

Set V bit for hwcap if misa is set.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1793
Signed-off-by: Nathan Egge <negge@xiph.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Tested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230803131424.40744-1-negge@xiph.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/elfload.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 51591a1d94..c9e176a9f6 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1710,7 +1710,8 @@ static uint32_t get_elf_hwcap(void)
 #define MISA_BIT(EXT) (1 << (EXT - 'A'))
     RISCVCPU *cpu = RISCV_CPU(thread_cpu);
     uint32_t mask = MISA_BIT('I') | MISA_BIT('M') | MISA_BIT('A')
-                    | MISA_BIT('F') | MISA_BIT('D') | MISA_BIT('C');
+                    | MISA_BIT('F') | MISA_BIT('D') | MISA_BIT('C')
+                    | MISA_BIT('V');
 
     return cpu->env.misa_ext & mask;
 #undef MISA_BIT
-- 
2.34.1

[PATCH v9 07/24] linux-user: Do not call get_errno() in do_brk()

[Nathan Egge]

On 2023-08-04 18:00, Richard Henderson wrote:
> From: Akihiko Odaki <akihiko.odaki@daynix.com>
>
> Later the returned value is compared with -1, and negated errno is not
> expected.
>
> Fixes: 00faf08c95 ("linux-user: Don't use MAP_FIXED in do_brk()")
> Reviewed-by: Helge Deller <deller@gmx.de>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Message-Id: <20230802071754.14876-4-akihiko.odaki@daynix.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/syscall.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 95727a816a..b9d2ec02f9 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -862,9 +862,9 @@ abi_long do_brk(abi_ulong brk_val)
>       */
>      if (new_host_brk_page > brk_page) {
>          new_alloc_size = new_host_brk_page - brk_page;
> -        mapped_addr = get_errno(target_mmap(brk_page, new_alloc_size,
> -                                        PROT_READ|PROT_WRITE,
> -                                        MAP_ANON|MAP_PRIVATE, 0, 0));
> +        mapped_addr = target_mmap(brk_page, new_alloc_size,
> +                                  PROT_READ|PROT_WRITE,
> +                                  MAP_ANON|MAP_PRIVATE, 0, 0);
>      } else {
>          new_alloc_size = 0;
>          mapped_addr = brk_page;
> -- 
> 2.34.1

This patch is triggering a gitlab pipeline failure in Richard's tcg-next 
branch:

https://gitlab.com/rth7680/qemu/-/pipelines/956532662

It can be reproduced locally by adding a git remote for rth7680 and then 
running:

$ git checkout rth7680/tcg-next
$ .gitlab-ci.d/check-patch.py

Checking all commits since c26d005e62f4fd177dae0cd70c24cb96761edebc...

f7cca41b17c809958a7f04b7d7f64af40d64e645:31: ERROR: spaces required 
around that '|' (ctx:VxV)
f7cca41b17c809958a7f04b7d7f64af40d64e645:32: ERROR: spaces required 
around that '|' (ctx:VxV)
total: 2 errors, 0 warnings, 12 lines checked
     ❌ FAIL one or more commits failed scripts/checkpatch.pl

The linux-user/syscall.c has many such places where this style check is 
failing. Should these be fixed in a separate patch?

Sincerely,

Nathan

Re: [PATCH v9 07/24] linux-user: Do not call get_errno() in do_brk()

[Richard Henderson]

On 8/4/23 16:40, Nathan Egge wrote:
> The linux-user/syscall.c has many such places where this style check is failing. Should 
> these be fixed in a separate patch?

Yes, eventually.


r~

Re: [PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Michael Tokarev]

05.08.2023 01:00, Richard Henderson wrpte:
> Supercedes: 20230804014517.6361-1-richard.henderson@linaro.org
> ("[PATCH for-8.1 v8 00/17] linux-user: brk fixes")
> 
> Changes for linux-user brk v9:
>    Recover some changes that should have been in v8, had I
>    generated the patches from the correct tree:
>      - bsd-user: Remove last_brk
>      - Fix typos in patch 15 ("Define ELF_ET_DYN_BASE...")
>      - Disable -Werror=type-limits in patch 13
>        ("linux-user: Adjust task_unmapped_base")

FWIW.

qemu-8.1 rc, with or without this patch set, does not work in
old aarch64 environment at all. F.e. ubuntu xenial or debian
jessie, like this:

# chroot /tmp/jessie-arm64/
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault

dash works, but bash or ls gives such sigsegv.

$ gdb qemu-aarch64 /tmp/jessie-arm64/core
GNU gdb (Debian 13.1-3) 13.1
...
[New LWP 2021520]
[New LWP 2021522]

warning: Section `.reg-xstate/2021520' in core file too small.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/tmp/qemu-aarch64 /bin/ls'.
Program terminated with signal SIGSEGV, Segmentation fault.

warning: Section `.reg-xstate/2021520' in core file too small.
#0  0x00007fa931538c31 in sigsuspend ()
[Current thread is 1 (Thread 0x5555573144c0 (LWP 2021520))]
warning: File "/build/qemu/test/.gdbinit" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
	add-auto-load-safe-path /build/qemu/test/.gdbinit
line to your configuration file "/home/mjt/.config/gdb/gdbinit".
To completely disable this security protection add
	set auto-load safe-path /
line to your configuration file "/home/mjt/.config/gdb/gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
	info "(gdb)Auto-loading safe path"
(gdb) bt
#0  0x00007fa931538c31 in sigsuspend ()
#1  0x00007fa93136f670 in dump_core_and_abort (cpu_env=cpu_env@entry=0x555557328800, target_sig=target_sig@entry=11) at ../linux-user/signal.c:747
#2  0x00007fa93136f9f5 in handle_pending_signal (cpu_env=0x555557328800, sig=11, k=0x555557390d80) at ../linux-user/signal.c:1068
#3  0x00007fa9313716b5 in process_pending_signals (cpu_env=cpu_env@entry=0x555557328800) at ../linux-user/signal.c:1143
#4  0x00007fa93118f09a in cpu_loop (env=env@entry=0x555557328800) at ../linux-user/aarch64/cpu_loop.c:179
#5  0x00007fa93118a498 in main (argc=<optimized out>, argv=0x7ffea05e15d8, envp=<optimized out>) at ../linux-user/main.c:1014
(gdb) frame 2
#2  0x00007fa93136f9f5 in handle_pending_signal (cpu_env=0x555557328800, sig=11, k=0x555557390d80) at ../linux-user/signal.c:1068
1068	        dump_core_and_abort(cpu_env, sig);
(gdb) frame 3
#3  0x00007fa9313716b5 in process_pending_signals (cpu_env=cpu_env@entry=0x555557328800) at ../linux-user/signal.c:1143
1143	            handle_pending_signal(cpu_env, sig, &ts->sync_signal);
(gdb) l
1138	                || sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) {
1139	                sigdelset(&ts->signal_mask, target_to_host_signal_table[sig]);
1140	                sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
1141	            }
1142	
1143	            handle_pending_signal(cpu_env, sig, &ts->sync_signal);
1144	        }
1145	
1146	        for (sig = 1; sig <= TARGET_NSIG; sig++) {
1147	            blocked_set = ts->in_sigsuspend ?
(gdb)


Is it worth to bisect?

/mjt

Re: [PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Michael Tokarev]

05.08.2023 16:28, Michael Tokarev wrote:
...
> qemu-8.1 rc, with or without this patch set, does not work in
> old aarch64 environment at all. F.e. ubuntu xenial or debian
> jessie, like this:
> 
> # chroot /tmp/jessie-arm64/
> qemu: uncaught target signal 11 (Segmentation fault) - core dumped
> Segmentation fault
> 
> dash works, but bash or ls gives such sigsegv
...
> Is it worth to bisect?

Since it was kinda trivial to bisect, I just did. And here's the
result:

commit 59b6b42cd3446862567637f3a7ab31d69c9bef51
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Tue Jun 6 10:19:39 2023 +0100

     target/arm: Enable FEAT_LSE2 for -cpu max

Reverting this patch on top of current master makes old linuxes
to work again.

/mjt

Re: [PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Richard Henderson]

On 8/5/23 06:51, Michael Tokarev wrote:
> 05.08.2023 16:28, Michael Tokarev wrote:
> ...
>> qemu-8.1 rc, with or without this patch set, does not work in
>> old aarch64 environment at all. F.e. ubuntu xenial or debian
>> jessie, like this:
>>
>> # chroot /tmp/jessie-arm64/
>> qemu: uncaught target signal 11 (Segmentation fault) - core dumped
>> Segmentation fault
>>
>> dash works, but bash or ls gives such sigsegv
> ...
>> Is it worth to bisect?
> 
> Since it was kinda trivial to bisect, I just did. And here's the
> result:
> 
> commit 59b6b42cd3446862567637f3a7ab31d69c9bef51
> Author: Richard Henderson <richard.henderson@linaro.org>
> Date:   Tue Jun 6 10:19:39 2023 +0100
> 
>      target/arm: Enable FEAT_LSE2 for -cpu max
> 
> Reverting this patch on top of current master makes old linuxes
> to work again.

What is your host?  That's probably the only relevant thing.


r~

Re: [PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Michael Tokarev]

05.08.2023 17:01, Richard Henderson wrote:

>> Since it was kinda trivial to bisect, I just did. And here's the
>> result:
>>
>> commit 59b6b42cd3446862567637f3a7ab31d69c9bef51
>> Author: Richard Henderson <richard.henderson@linaro.org>
>> Date:   Tue Jun 6 10:19:39 2023 +0100
>>
>>      target/arm: Enable FEAT_LSE2 for -cpu max
>>
>> Reverting this patch on top of current master makes old linuxes
>> to work again.
> 
> What is your host?  That's probably the only relevant thing.

It's running on amd64 machine (AMD Ryzen 7 PRO 5750G), current debian
bookworm, kernel 6.1.0-10-amd64 (for qemu-user-static only architecture
and the kernel matters, I guess).

I noticed this while trying to reproduce
  https://gitlab.com/qemu-project/qemu/-/issues/1763

/mjt

Re: [PATCH v9 for-8.1 00/24] linux-user + tcg patch queue

[Michael Tokarev]

Please excuse me for jijacking this thread. I was sure it is something
relevant to the issues we were dealing with, - since I remember qemu-aarch64
segfaulting with intermediate patches in this area.

For this aarch64-user segfault, my guess is that older software isn't
prepared for -cpu max.

/mjt