uml: fix stub address calculations
Jeff Dike [Tue, 16 Oct 2007 08:27:33 +0000 (01:27 -0700)]
The calculation of CONFIG_STUB_CODE and CONFIG_STUB_DATA didn't take into
account anything but 3G/1G and 2G/2G, leaving the other vmsplits out in the
cold.

I'd rather not duplicate the four known host vmsplit cases for each of these
symbols.  I'd also like to calculate them based on the highest userspace
address.

The Kconfig language seems not to allow calculation of hex constants, so I
moved this to as-layout.h.  CONFIG_STUB_CODE, CONFIG_STUB_DATA, and
CONFIG_STUB_START are now gone.  In their place are STUB_CODE, STUB_DATA, and
STUB_START in as-layout.h.

i386 and x86_64 seem to differ as to whether an unadorned constant is an int
or a long, so I cast them to unsigned long so they can be printed
consistently.  However, they are also used in stub.S, where C types don't work
so well.  So, there are ASM_ versions of these constants for use in stub.S.  I
also ifdef-ed the non-asm-friendly portion of as-layout.h.

With this in place, most of the rest of this patch is changing CONFIG_STUB_*
to STUB_*, except in stub.S, where they are changed to ASM_STUB_*.

defconfig has the old symbols deleted.

I also print these addresses out in case there is any problem mapping them on
the host.

The two stub.S files had some trailing whitespace, so that is cleaned up here.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

18 files changed:
arch/um/Kconfig.i386
arch/um/Kconfig.x86_64
arch/um/defconfig
arch/um/include/as-layout.h
arch/um/include/sysdep-i386/stub.h
arch/um/include/sysdep-x86_64/stub.h
arch/um/kernel/exec.c
arch/um/kernel/skas/clone.c
arch/um/kernel/skas/mmu.c
arch/um/kernel/skas/process.c
arch/um/kernel/tlb.c
arch/um/kernel/um_arch.c
arch/um/os-Linux/skas/mem.c
arch/um/os-Linux/skas/process.c
arch/um/sys-i386/stub.S
arch/um/sys-i386/stub_segv.c
arch/um/sys-x86_64/stub.S
arch/um/sys-x86_64/stub_segv.c

index d6cffb2..9876d80 100644 (file)
@@ -65,20 +65,6 @@ config 3_LEVEL_PGTABLES
        However, this it experimental on 32-bit architectures, so if unsure say
        N (on x86-64 it's automatically enabled, instead, as it's safe there).
 
-config STUB_CODE
-       hex
-       default 0xbfffe000 if !HOST_VMSPLIT_2G
-       default 0x7fffe000 if HOST_VMSPLIT_2G
-
-config STUB_DATA
-       hex
-       default 0xbffff000 if !HOST_VMSPLIT_2G
-       default 0x7ffff000 if HOST_VMSPLIT_2G
-
-config STUB_START
-       hex
-       default STUB_CODE
-
 config ARCH_HAS_SC_SIGNALS
        bool
        default y
index f60e9e5..d632e9a 100644 (file)
@@ -17,24 +17,12 @@ config SEMAPHORE_SLEEPERS
 
 config TOP_ADDR
        hex
-       default 0x80000000
+       default 0x7fc0000000
 
 config 3_LEVEL_PGTABLES
        bool
        default y
 
-config STUB_CODE
-       hex
-       default 0x7fbfffe000
-
-config STUB_DATA
-       hex
-       default 0x7fbffff000
-
-config STUB_START
-       hex
-       default STUB_CODE
-
 config ARCH_HAS_SC_SIGNALS
        bool
        default n
index 1cbbe98..f609ede 100644 (file)
@@ -59,9 +59,6 @@ CONFIG_SEMAPHORE_SLEEPERS=y
 # CONFIG_HOST_2G_2G is not set
 CONFIG_TOP_ADDR=0xc0000000
 # CONFIG_3_LEVEL_PGTABLES is not set
-CONFIG_STUB_CODE=0xbfffe000
-CONFIG_STUB_DATA=0xbffff000
-CONFIG_STUB_START=0xbfffe000
 CONFIG_ARCH_HAS_SC_SIGNALS=y
 CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA=y
 CONFIG_GENERIC_HWEIGHT=y
index 2f16a1c..a5cdf95 100644 (file)
@@ -6,6 +6,28 @@
 #ifndef __START_H__
 #define __START_H__
 
+#include "uml-config.h"
+#include "kern_constants.h"
+
+/*
+ * Assembly doesn't want any casting, but C does, so define these
+ * without casts here, and define new symbols with casts inside the C
+ * section.
+ */
+#define ASM_STUB_CODE (UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
+#define ASM_STUB_DATA (UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
+#define ASM_STUB_START ASM_STUB_CODE
+
+/*
+ * This file is included by the assembly stubs, which just want the
+ * definitions above.
+ */
+#ifndef __ASSEMBLY__
+
+#define STUB_CODE ((unsigned long) ASM_STUB_CODE)
+#define STUB_DATA ((unsigned long) ASM_STUB_DATA)
+#define STUB_START ((unsigned long) ASM_STUB_START)
+
 #include "sysdep/ptrace.h"
 
 struct cpu_task {
@@ -32,3 +54,5 @@ extern int linux_main(int argc, char **argv);
 extern void (*sig_info[])(int, struct uml_pt_regs *);
 
 #endif
+
+#endif
index 19c85f3..8c097b8 100644 (file)
@@ -9,6 +9,7 @@
 #include <sys/mman.h>
 #include <asm/ptrace.h>
 #include <asm/unistd.h>
+#include "as-layout.h"
 #include "stub-data.h"
 #include "kern_constants.h"
 #include "uml-config.h"
@@ -89,12 +90,12 @@ static inline void remap_stack(int fd, unsigned long offset)
 {
        __asm__ volatile ("movl %%eax,%%ebp ; movl %0,%%eax ; int $0x80 ;"
                          "movl %7, %%ebx ; movl %%eax, (%%ebx)"
-                         : : "g" (STUB_MMAP_NR), "b" (UML_CONFIG_STUB_DATA), 
-                           "c" (UM_KERN_PAGE_SIZE), 
+                         : : "g" (STUB_MMAP_NR), "b" (STUB_DATA),
+                           "c" (UM_KERN_PAGE_SIZE),
                            "d" (PROT_READ | PROT_WRITE),
-                           "S" (MAP_FIXED | MAP_SHARED), "D" (fd), 
-                           "a" (offset), 
-                           "i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err) 
+                           "S" (MAP_FIXED | MAP_SHARED), "D" (fd),
+                           "a" (offset),
+                           "i" (&((struct stub_data *) STUB_DATA)->err)
                          : "memory");
 }
 
index 92e989f..655f9c2 100644 (file)
@@ -9,6 +9,7 @@
 #include <sys/mman.h>
 #include <asm/unistd.h>
 #include <sysdep/ptrace_user.h>
+#include "as-layout.h"
 #include "stub-data.h"
 #include "kern_constants.h"
 #include "uml-config.h"
@@ -94,13 +95,13 @@ static inline void remap_stack(long fd, unsigned long offset)
 {
        __asm__ volatile ("movq %4,%%r10 ; movq %5,%%r8 ; "
                          "movq %6, %%r9; " __syscall "; movq %7, %%rbx ; "
-                         "movq %%rax, (%%rbx)": 
-                         : "a" (STUB_MMAP_NR), "D" (UML_CONFIG_STUB_DATA), 
-                           "S" (UM_KERN_PAGE_SIZE), 
-                           "d" (PROT_READ | PROT_WRITE), 
-                            "g" (MAP_FIXED | MAP_SHARED), "g" (fd), 
+                         "movq %%rax, (%%rbx)":
+                         : "a" (STUB_MMAP_NR), "D" (STUB_DATA),
+                           "S" (UM_KERN_PAGE_SIZE),
+                           "d" (PROT_READ | PROT_WRITE),
+                            "g" (MAP_FIXED | MAP_SHARED), "g" (fd),
                            "g" (offset),
-                           "i" (&((struct stub_data *) UML_CONFIG_STUB_DATA)->err)
+                           "i" (&((struct stub_data *) STUB_DATA)->err)
                          : __syscall_clobber, "r10", "r8", "r9" );
 }
 
index 7c77ade..8196450 100644 (file)
@@ -11,6 +11,7 @@
 #include "asm/current.h"
 #include "asm/processor.h"
 #include "asm/uaccess.h"
+#include "as-layout.h"
 #include "mem_user.h"
 #include "skas.h"
 #include "os.h"
@@ -18,7 +19,7 @@
 void flush_thread(void)
 {
        void *data = NULL;
-       unsigned long end = proc_mm ? task_size : CONFIG_STUB_START;
+       unsigned long end = proc_mm ? task_size : STUB_START;
        int ret;
 
        arch_flush_thread(&current->thread.arch);
index 47b812b..d119f4f 100644 (file)
@@ -4,6 +4,7 @@
 #include <sys/time.h>
 #include <asm/unistd.h>
 #include <asm/page.h>
+#include "as-layout.h"
 #include "ptrace_user.h"
 #include "skas.h"
 #include "stub-data.h"
 void __attribute__ ((__section__ (".__syscall_stub")))
 stub_clone_handler(void)
 {
-       struct stub_data *data = (struct stub_data *) UML_CONFIG_STUB_DATA;
+       struct stub_data *data = (struct stub_data *) STUB_DATA;
        long err;
 
        err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
-                           UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE / 2 -
-                           sizeof(void *));
+                           STUB_DATA + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
        if(err != 0)
                goto out;
 
index ae79888..f859ec3 100644 (file)
@@ -7,6 +7,7 @@
 #include "linux/sched.h"
 #include "asm/pgalloc.h"
 #include "asm/pgtable.h"
+#include "as-layout.h"
 #include "os.h"
 #include "skas.h"
 
@@ -83,12 +84,12 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
                 */
                mm->pgd[USER_PTRS_PER_PGD] = __pgd(0);
 
-               ret = init_stub_pte(mm, CONFIG_STUB_CODE,
+               ret = init_stub_pte(mm, STUB_CODE,
                                    (unsigned long) &__syscall_stub_start);
                if (ret)
                        goto out_free;
 
-               ret = init_stub_pte(mm, CONFIG_STUB_DATA, stack);
+               ret = init_stub_pte(mm, STUB_DATA, stack);
                if (ret)
                        goto out_free;
 
index 0297e63..fce389c 100644 (file)
@@ -18,7 +18,7 @@ int new_mm(unsigned long stack)
                return fd;
 
        if (skas_needs_stub)
-               map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack);
+               map_stub_pages(fd, STUB_CODE, STUB_DATA, stack);
 
        return fd;
 }
index 942f20e..f4a0e40 100644 (file)
@@ -485,8 +485,8 @@ void __flush_tlb_one(unsigned long addr)
 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
                      unsigned long end_addr, int force)
 {
-       if (!proc_mm && (end_addr > CONFIG_STUB_START))
-               end_addr = CONFIG_STUB_START;
+       if (!proc_mm && (end_addr > STUB_START))
+               end_addr = STUB_START;
 
        fix_range_common(mm, start_addr, end_addr, force);
 }
@@ -510,7 +510,7 @@ void flush_tlb_mm(struct mm_struct *mm)
        if (atomic_read(&mm->mm_users) == 0)
                return;
 
-       end = proc_mm ? task_size : CONFIG_STUB_START;
+       end = proc_mm ? task_size : STUB_START;
        fix_range(mm, 0, end, 0);
 }
 
index 1993e5e..f1c7139 100644 (file)
@@ -242,7 +242,8 @@ static unsigned long set_task_sizes_skas(unsigned long *task_size_out)
 
        if (!skas_needs_stub)
                *task_size_out = host_task_size;
-       else *task_size_out = CONFIG_STUB_START & PGDIR_MASK;
+       else
+               *task_size_out = STUB_START & PGDIR_MASK;
 
        return host_task_size;
 }
index d58d111..484e68f 100644 (file)
@@ -10,6 +10,7 @@
 #include <sys/mman.h>
 #include "init.h"
 #include "kern_constants.h"
+#include "as-layout.h"
 #include "mm_id.h"
 #include "os.h"
 #include "proc_mm.h"
@@ -40,7 +41,7 @@ static unsigned long syscall_regs[MAX_REG_NR];
 static int __init init_syscall_regs(void)
 {
        get_safe_registers(syscall_regs);
-       syscall_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+       syscall_regs[REGS_IP_INDEX] = STUB_CODE +
                ((unsigned long) &batch_syscall_stub -
                 (unsigned long) &__syscall_stub_start);
        return 0;
@@ -93,8 +94,7 @@ static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
        ret = *((unsigned long *) mm_idp->stack);
        offset = *((unsigned long *) mm_idp->stack + 1);
        if (offset) {
-               data = (unsigned long *)(mm_idp->stack +
-                                        offset - UML_CONFIG_STUB_DATA);
+               data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
                printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, "
                       "data = %p\n", ret, offset, data);
                syscall = (unsigned long *)((unsigned long)data + data[0]);
@@ -182,7 +182,7 @@ long syscall_stub_data(struct mm_id * mm_idp,
        memcpy(stack + 1, data, data_count * sizeof(long));
 
        *stub_addr = (void *)(((unsigned long)(stack + 1) &
-                              ~UM_KERN_PAGE_MASK) + UML_CONFIG_STUB_DATA);
+                              ~UM_KERN_PAGE_MASK) + STUB_DATA);
 
        return 0;
 }
index 8548f12..e60d6e6 100644 (file)
@@ -191,22 +191,23 @@ static int userspace_tramp(void *stack)
                int fd;
                unsigned long long offset;
                fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
-               addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE,
+               addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
                              PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
                if (addr == MAP_FAILED) {
-                       printk(UM_KERN_ERR "mapping mmap stub failed, "
-                              "errno = %d\n", errno);
+                       printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
+                              "errno = %d\n", STUB_CODE, errno);
                        exit(1);
                }
 
                if (stack != NULL) {
                        fd = phys_mapping(to_phys(stack), &offset);
-                       addr = mmap((void *) UML_CONFIG_STUB_DATA,
+                       addr = mmap((void *) STUB_DATA,
                                    UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
                                    MAP_FIXED | MAP_SHARED, fd, offset);
                        if (addr == MAP_FAILED) {
                                printk(UM_KERN_ERR "mapping segfault stack "
-                                      "failed, errno = %d\n", errno);
+                                      "at 0x%lx failed, errno = %d\n",
+                                      STUB_DATA, errno);
                                exit(1);
                        }
                }
@@ -214,11 +215,11 @@ static int userspace_tramp(void *stack)
        if (!ptrace_faultinfo && (stack != NULL)) {
                struct sigaction sa;
 
-               unsigned long v = UML_CONFIG_STUB_CODE +
+               unsigned long v = STUB_CODE +
                                  (unsigned long) stub_segv_handler -
                                  (unsigned long) &__syscall_stub_start;
 
-               set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE);
+               set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
                sigemptyset(&sa.sa_mask);
                sigaddset(&sa.sa_mask, SIGIO);
                sigaddset(&sa.sa_mask, SIGWINCH);
@@ -382,10 +383,10 @@ static int __init init_thread_regs(void)
 {
        get_safe_registers(thread_regs);
        /* Set parent's instruction pointer to start of clone-stub */
-       thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+       thread_regs[REGS_IP_INDEX] = STUB_CODE +
                                (unsigned long) stub_clone_handler -
                                (unsigned long) &__syscall_stub_start;
-       thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE -
+       thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
                sizeof(void *);
 #ifdef __SIGNAL_FRAMESIZE
        thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
@@ -443,7 +444,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
         * child's stack and check it.
         */
        wait_stub_done(pid);
-       if (child_data->err != UML_CONFIG_STUB_DATA)
+       if (child_data->err != STUB_DATA)
                panic("copy_context_skas0 - stub-child reports error %ld\n",
                      child_data->err);
 
index 6a70d9a..e730772 100644 (file)
@@ -1,4 +1,5 @@
 #include "uml-config.h"
+#include "as-layout.h"
 
        .globl syscall_stub
 .section .__syscall_stub, "x"
@@ -6,7 +7,7 @@
        .globl batch_syscall_stub
 batch_syscall_stub:
        /* load pointer to first operation */
-       mov     $(UML_CONFIG_STUB_DATA+8), %esp
+       mov     $(ASM_STUB_DATA+8), %esp
 
 again:
        /* load length of additional data */
@@ -14,12 +15,12 @@ again:
 
        /* if(length == 0) : end of list */
        /* write possible 0 to header */
-       mov     %eax, UML_CONFIG_STUB_DATA+4
+       mov     %eax, ASM_STUB_DATA+4
        cmpl    $0, %eax
        jz      done
 
        /* save current pointer */
-       mov     %esp, UML_CONFIG_STUB_DATA+4
+       mov     %esp, ASM_STUB_DATA+4
 
        /* skip additional data */
        add     %eax, %esp
@@ -45,7 +46,7 @@ again:
 
 done:
        /* save return value */
-       mov     %eax, UML_CONFIG_STUB_DATA
+       mov     %eax, ASM_STUB_DATA
 
        /* stop */
        int3
index 2355dc1..b3999cb 100644 (file)
@@ -6,6 +6,7 @@
 #include <signal.h>
 #include <sys/select.h> /* The only way I can see to get sigset_t */
 #include <asm/unistd.h>
+#include "as-layout.h"
 #include "uml-config.h"
 #include "sysdep/stub.h"
 #include "sysdep/sigcontext.h"
@@ -17,8 +18,7 @@ stub_segv_handler(int sig)
        struct sigcontext *sc = (struct sigcontext *) (&sig + 1);
        int pid;
 
-       GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
-                             sc);
+       GET_FAULTINFO_FROM_SC(*((struct faultinfo *) STUB_DATA), sc);
 
        pid = stub_syscall0(__NR_getpid);
        stub_syscall2(__NR_kill, pid, SIGUSR1);
index 03c2797..4afe204 100644 (file)
@@ -1,4 +1,5 @@
 #include "uml-config.h"
+#include "as-layout.h"
 
        .globl syscall_stub
 .section .__syscall_stub, "x"
@@ -7,18 +8,18 @@ syscall_stub:
        /* We don't have 64-bit constants, so this constructs the address
         * we need.
         */
-       movq    $(UML_CONFIG_STUB_DATA >> 32), %rbx
+       movq    $(ASM_STUB_DATA >> 32), %rbx
        salq    $32, %rbx
-       movq    $(UML_CONFIG_STUB_DATA & 0xffffffff), %rcx
+       movq    $(ASM_STUB_DATA & 0xffffffff), %rcx
        or      %rcx, %rbx
        movq    %rax, (%rbx)
        int3
 
        .globl batch_syscall_stub
 batch_syscall_stub:
-       mov     $(UML_CONFIG_STUB_DATA >> 32), %rbx
+       mov     $(ASM_STUB_DATA >> 32), %rbx
        sal     $32, %rbx
-       mov     $(UML_CONFIG_STUB_DATA & 0xffffffff), %rax
+       mov     $(ASM_STUB_DATA & 0xffffffff), %rax
        or      %rax, %rbx
        /* load pointer to first operation */
        mov     %rbx, %rsp
index 652fa34..3afb590 100644 (file)
@@ -6,6 +6,7 @@
 #include <stddef.h>
 #include <signal.h>
 #include <asm/unistd.h>
+#include "as-layout.h"
 #include "uml-config.h"
 #include "sysdep/sigcontext.h"
 #include "sysdep/faultinfo.h"
@@ -33,7 +34,7 @@ stub_segv_handler(int sig)
         int pid;
 
        __asm__ __volatile__("movq %%rdx, %0" : "=g" (uc) :);
-       GET_FAULTINFO_FROM_SC(*((struct faultinfo *) UML_CONFIG_STUB_DATA),
+       GET_FAULTINFO_FROM_SC(*((struct faultinfo *) STUB_DATA),
                              &uc->uc_mcontext);
 
        pid = stub_syscall0(__NR_getpid);