Index: kernel/arch/amd64/include/syscall.h =================================================================== --- kernel/arch/amd64/include/syscall.h (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/amd64/include/syscall.h (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -36,6 +36,4 @@ #define KERN_amd64_SYSCALL_H_ -#include - extern void syscall_setup_cpu(void); Index: kernel/arch/ia32/Makefile.inc =================================================================== --- kernel/arch/ia32/Makefile.inc (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/Makefile.inc (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -161,3 +161,4 @@ arch/$(ARCH)/src/boot/memmap.c \ arch/$(ARCH)/src/fpu_context.c \ - arch/$(ARCH)/src/debugger.c + arch/$(ARCH)/src/debugger.c \ + arch/$(ARCH)/src/syscall.c Index: kernel/arch/ia32/include/asm.h =================================================================== --- kernel/arch/ia32/include/asm.h (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/include/asm.h (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -248,4 +248,20 @@ } +/** Write to MSR */ +static inline void write_msr(uint32_t msr, uint64_t value) +{ + asm volatile ("wrmsr" : : "c" (msr), "a" ((uint32_t)(value)), + "d" ((uint32_t)(value >> 32))); +} + +static inline uint64_t read_msr(uint32_t msr) +{ + uint32_t ax, dx; + + asm volatile ("rdmsr" : "=a"(ax), "=d"(dx) : "c" (msr)); + return ((uint64_t)dx << 32) | ax; +} + + /** Return base address of current stack * Index: kernel/arch/ia32/include/cpu.h =================================================================== --- kernel/arch/ia32/include/cpu.h (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/include/cpu.h (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -36,9 +36,18 @@ #define KERN_ia32_CPU_H_ +#define EFLAGS_IF (1 << 9) +#define EFLAGS_RF (1 << 16) + +#define CR4_OSFXSR_MASK (1<<9) + +/* Support for SYSENTER and SYSEXIT */ +#define IA32_MSR_SYSENTER_CS 0x174 +#define IA32_MSR_SYSENTER_ESP 0x175 +#define IA32_MSR_SYSENTER_EIP 0x176 + +#ifndef __ASM__ + #include #include - -#define EFLAGS_IF (1 << 9) -#define EFLAGS_RF (1 << 16) typedef struct { @@ -52,6 +61,5 @@ } cpu_arch_t; - -#define CR4_OSFXSR_MASK (1<<9) +#endif #endif Index: kernel/arch/ia32/include/syscall.h =================================================================== --- kernel/arch/ia32/include/syscall.h (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) +++ kernel/arch/ia32/include/syscall.h (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -0,0 +1,1 @@ +../../amd64/include/syscall.h Index: kernel/arch/ia32/src/asm.S =================================================================== --- kernel/arch/ia32/src/asm.S (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/src/asm.S (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -147,4 +147,43 @@ popfl .endm + +/* + * The SYSENTER syscall mechanism can be used for syscalls with + * four or fewer arguments. To pass these four arguments, we + * use four registers: EDX, ECX, EBX, ESI. The syscall number + * is passed in EAX. We use EDI to remember the return address + * and EBP to remember the stack. The INT-based syscall mechanism + * can actually handle six arguments plus the syscall number + * entirely in registers. + */ +.global sysenter_handler +sysenter_handler: + pushl %ebp # remember user stack + pushl %edi # remember return user address + + pushl %gs # remember TLS + + pushl %eax # syscall number + subl $8, %esp # unused sixth and fifth argument + pushl %esi # fourth argument + pushl %ebx # third argument + pushl %ecx # second argument + pushl %edx # first argument + + movw $16, %ax + movw %ax, %ds + movw %ax, %es + + cld + call syscall_handler + addl $28, %esp # remove arguments from stack + + pop %gs # restore TLS + + pop %edx # prepare return EIP for SYSEXIT + pop %ecx # prepare userspace ESP for SYSEXIT + + sysexit # return to userspace + ## Declare interrupt handlers Index: kernel/arch/ia32/src/cpu/cpu.c =================================================================== --- kernel/arch/ia32/src/cpu/cpu.c (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/src/cpu/cpu.c (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -43,4 +43,5 @@ #include +#include /* @@ -124,4 +125,7 @@ ); } + + /* Setup fast SYSENTER/SYSEXIT syscalls */ + syscall_setup_cpu(); } Index: kernel/arch/ia32/src/proc/scheduler.c =================================================================== --- kernel/arch/ia32/src/proc/scheduler.c (revision d364e94360c20325ba21bb69e6ac2542ade79708) +++ kernel/arch/ia32/src/proc/scheduler.c (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -59,6 +59,12 @@ void before_thread_runs_arch(void) { - CPU->arch.tss->esp0 = (uintptr_t) &THREAD->kstack[THREAD_STACK_SIZE - + uintptr_t kstk = (uintptr_t) &THREAD->kstack[THREAD_STACK_SIZE - SP_DELTA]; + + /* Set kernel stack for CP3 -> CPL0 switch via SYSENTER */ + write_msr(IA32_MSR_SYSENTER_ESP, kstk); + + /* Set kernel stack for CPL3 -> CPL0 switch via interrupt */ + CPU->arch.tss->esp0 = kstk; CPU->arch.tss->ss0 = selector(KDATA_DES); Index: kernel/arch/ia32/src/syscall.c =================================================================== --- kernel/arch/ia32/src/syscall.c (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) +++ kernel/arch/ia32/src/syscall.c (revision c61d34be34099f5ca3cf83937a9935c4e09a9773) @@ -0,0 +1,53 @@ +/* + * Copyright (c) 2008 Jakub Jermar + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** @addtogroup ia32 + * @{ + */ +/** @file + */ + +#include +#include +#include +#include +#include + +/** Enable & setup support for SYSENTER/SYSEXIT */ +void syscall_setup_cpu(void) +{ + extern void sysenter_handler(void); + + /* set kernel mode CS selector */ + write_msr(IA32_MSR_SYSENTER_CS, selector(KTEXT_DES)); + /* set kernel mode entry point */ + write_msr(IA32_MSR_SYSENTER_EIP, (uint32_t) sysenter_handler); +} + +/** @} + */