src/system/kernel/arch/x86/32/syscalls.cpp

   1 /*
   2  * Copyright 2008-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
   3  * Copyright 2007, Travis Geiselbrecht. All rights reserved.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7
   8 #include "x86_syscalls.h"
   9
  10 #include <string.h>
  11
  12 #include <KernelExport.h>
  13
  14 #include <commpage.h>
  15 #include <cpu.h>
  16 #include <elf.h>
  17 #include <smp.h>
  18
  19
  20 // user syscall assembly stubs
  21 extern "C" void x86_user_syscall_int(void);
  22 extern unsigned int x86_user_syscall_int_end;
  23 extern "C" void x86_user_syscall_sysenter(void);
  24 extern unsigned int x86_user_syscall_sysenter_end;
  25
  26 // sysenter handler
  27 extern "C" void x86_sysenter();
  28
  29
  30 void (*gX86SetSyscallStack)(addr_t stackTop) = NULL;
  31
  32
  33 extern int memcpy_end;
  34 extern int memset_end;
  35
  36
  37 static bool
  38 all_cpus_have_feature(enum x86_feature_type type, int feature)
  39 {
  40         int i;
  41         int cpuCount = smp_get_num_cpus();
  42
  43         for (i = 0; i < cpuCount; i++) {
  44                 if (!(gCPU[i].arch.feature[type] & feature))
  45                         return false;
  46         }
  47
  48         return true;
  49 }
  50
  51
  52 static void
  53 set_intel_syscall_stack(addr_t stackTop)
  54 {
  55         x86_write_msr(IA32_MSR_SYSENTER_ESP, stackTop);
  56 }
  57
  58
  59 static void
  60 init_intel_syscall_registers(void* dummy, int cpuNum)
  61 {
  62         x86_write_msr(IA32_MSR_SYSENTER_CS, KERNEL_CODE_SELECTOR);
  63         x86_write_msr(IA32_MSR_SYSENTER_ESP, 0);
  64         x86_write_msr(IA32_MSR_SYSENTER_EIP, (addr_t)x86_sysenter);
  65
  66         gX86SetSyscallStack = &set_intel_syscall_stack;
  67 }
  68
  69
  70 #if 0
  71 static void
  72 init_amd_syscall_registers(void* dummy, int cpuNum)
  73 {
  74         // TODO: ...
  75 }
  76 #endif
  77
  78
  79 // #pragma mark -
  80
  81
  82 void
  83 x86_initialize_syscall(void)
  84 {
  85         void* syscallCode = (void *)&x86_user_syscall_int;
  86         void* syscallCodeEnd = &x86_user_syscall_int_end;
  87
  88         // check syscall
  89         if (all_cpus_have_feature(FEATURE_COMMON, IA32_FEATURE_SEP)
  90                 && !(gCPU[0].arch.family == 6 && gCPU[0].arch.model < 3
  91                         && gCPU[0].arch.stepping < 3)) {
  92                 // Intel sysenter/sysexit
  93                 dprintf("initialize_commpage_syscall(): sysenter/sysexit supported\n");
  94
  95                 // the code to be used in userland
  96                 syscallCode = (void *)&x86_user_syscall_sysenter;
  97                 syscallCodeEnd = &x86_user_syscall_sysenter_end;
  98
  99                 // tell all CPUs to init their sysenter/sysexit related registers
 100                 call_all_cpus_sync(&init_intel_syscall_registers, NULL);
 101         } else if (all_cpus_have_feature(FEATURE_EXT_AMD,
 102                         IA32_FEATURE_AMD_EXT_SYSCALL)) {
 103                 // AMD syscall/sysret
 104                 dprintf("initialize_commpage_syscall(): syscall/sysret supported "
 105                         "-- not yet by Haiku, though");
 106         } else {
 107                 // no special syscall support
 108                 dprintf("initialize_commpage_syscall(): no special syscall support\n");
 109         }
 110
 111         // fill in the table entry
 112         size_t len = (size_t)((addr_t)syscallCodeEnd - (addr_t)syscallCode);
 113         addr_t position = fill_commpage_entry(COMMPAGE_ENTRY_X86_SYSCALL,
 114                 syscallCode, len);
 115
 116         // put the optimized functions into the commpage
 117         size_t memcpyLen = (addr_t)&memcpy_end - (addr_t)memcpy;
 118         addr_t memcpyPosition = fill_commpage_entry(COMMPAGE_ENTRY_X86_MEMCPY,
 119                 (const void*)memcpy, memcpyLen);
 120         size_t memsetLen = (addr_t)&memset_end - (addr_t)memset;
 121         addr_t memsetPosition = fill_commpage_entry(COMMPAGE_ENTRY_X86_MEMSET,
 122                 (const void*)memset, memsetLen);
 123
 124         // add syscall to the commpage image
 125         image_id image = get_commpage_image();
 126         elf_add_memory_image_symbol(image, "commpage_memcpy", memcpyPosition,
 127                 memcpyLen, B_SYMBOL_TYPE_TEXT);
 128         elf_add_memory_image_symbol(image, "commpage_memset", memsetPosition,
 129                 memsetLen, B_SYMBOL_TYPE_TEXT);
 130         elf_add_memory_image_symbol(image, "commpage_syscall", position, len,
 131                 B_SYMBOL_TYPE_TEXT);
 132 }