diff options
author | 2015-08-28 09:58:54 +0800 | |
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committer | 2015-09-01 12:44:00 +0800 | |
commit | e44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch) | |
tree | 66b09f592c55df2878107a468a91d21506104d3f /qemu/roms/seabios/src/stacks.c | |
parent | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff) |
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/roms/seabios/src/stacks.c')
-rw-r--r-- | qemu/roms/seabios/src/stacks.c | 827 |
1 files changed, 827 insertions, 0 deletions
diff --git a/qemu/roms/seabios/src/stacks.c b/qemu/roms/seabios/src/stacks.c new file mode 100644 index 000000000..1dbdfe9bb --- /dev/null +++ b/qemu/roms/seabios/src/stacks.c @@ -0,0 +1,827 @@ +// Code for manipulating stack locations. +// +// Copyright (C) 2009-2014 Kevin O'Connor <kevin@koconnor.net> +// +// This file may be distributed under the terms of the GNU LGPLv3 license. + +#include "biosvar.h" // GET_GLOBAL +#include "bregs.h" // CR0_PE +#include "fw/paravirt.h" // PORT_SMI_CMD +#include "hw/rtc.h" // rtc_use +#include "list.h" // hlist_node +#include "malloc.h" // free +#include "output.h" // dprintf +#include "romfile.h" // romfile_loadint +#include "stacks.h" // struct mutex_s +#include "util.h" // useRTC + +#define MAIN_STACK_MAX (1024*1024) + + +/**************************************************************** + * 16bit / 32bit calling + ****************************************************************/ + +struct { + u8 method; + u8 cmosindex; + u8 a20; + u16 ss, fs, gs; + struct descloc_s gdt; +} Call32Data VARLOW; + +#define C32_SLOPPY 1 +#define C32_SMM 2 + +int HaveSmmCall32 VARFSEG; + +// Backup state in preparation for call32_smm() +static void +call32_smm_prep(void) +{ + // Backup cmos index register and disable nmi + u8 cmosindex = inb(PORT_CMOS_INDEX); + outb(cmosindex | NMI_DISABLE_BIT, PORT_CMOS_INDEX); + inb(PORT_CMOS_DATA); + SET_LOW(Call32Data.cmosindex, cmosindex); + + // Backup ss + SET_LOW(Call32Data.ss, GET_SEG(SS)); + + SET_LOW(Call32Data.method, C32_SMM); +} + +// Restore state backed up during call32_smm() +static void +call32_smm_post(void) +{ + SET_LOW(Call32Data.method, 0); + SET_LOW(Call32Data.ss, 0); + + // Restore cmos index register + outb(GET_LOW(Call32Data.cmosindex), PORT_CMOS_INDEX); + inb(PORT_CMOS_DATA); +} + +#define ASM32_SWITCH16 " .pushsection .text.32fseg." UNIQSEC "\n .code16\n" +#define ASM32_BACK32 " .popsection\n .code32\n" +#define ASM16_SWITCH32 " .code32\n" +#define ASM16_BACK16 " .code16gcc\n" + +// Call a SeaBIOS C function in 32bit mode using smm trampoline +static u32 +call32_smm(void *func, u32 eax) +{ + ASSERT16(); + dprintf(9, "call32_smm %p %x\n", func, eax); + call32_smm_prep(); + u32 bkup_esp; + asm volatile( + // Backup esp / set esp to flat stack location + " movl %%esp, %0\n" + " movl %%ss, %%eax\n" + " shll $4, %%eax\n" + " addl %%eax, %%esp\n" + + // Transition to 32bit mode, call func, return to 16bit + " movl $" __stringify(CALL32SMM_CMDID) ", %%eax\n" + " movl $" __stringify(CALL32SMM_ENTERID) ", %%ecx\n" + " movl $(" __stringify(BUILD_BIOS_ADDR) " + 1f), %%ebx\n" + " outb %%al, $" __stringify(PORT_SMI_CMD) "\n" + " rep; nop\n" + " hlt\n" + + ASM16_SWITCH32 + "1:movl %1, %%eax\n" + " calll *%2\n" + " movl %%eax, %1\n" + + " movl $" __stringify(CALL32SMM_CMDID) ", %%eax\n" + " movl $" __stringify(CALL32SMM_RETURNID) ", %%ecx\n" + " movl $2f, %%ebx\n" + " outb %%al, $" __stringify(PORT_SMI_CMD) "\n" + " rep; nop\n" + " hlt\n" + + // Restore esp + ASM16_BACK16 + "2:movl %0, %%esp\n" + : "=&r" (bkup_esp), "+r" (eax) + : "r" (func) + : "eax", "ecx", "edx", "ebx", "cc", "memory"); + call32_smm_post(); + + dprintf(9, "call32_smm done %p %x\n", func, eax); + return eax; +} + +// 16bit handler code called from call16_smm() +u32 VISIBLE16 +call16_smm_helper(u32 eax, u32 edx, u32 (*func)(u32 eax, u32 edx)) +{ + if (!CONFIG_CALL32_SMM) + return eax; + call32_smm_post(); + u32 ret = func(eax, edx); + call32_smm_prep(); + return ret; +} + +static u32 +call16_smm(u32 eax, u32 edx, void *func) +{ + ASSERT32FLAT(); + if (!CONFIG_CALL32_SMM) + return eax; + func -= BUILD_BIOS_ADDR; + dprintf(9, "call16_smm %p %x %x\n", func, eax, edx); + u32 stackoffset = Call32Data.ss << 4; + asm volatile( + // Restore esp + " subl %0, %%esp\n" + + // Transition to 16bit mode, call func, return to 32bit + " movl $" __stringify(CALL32SMM_CMDID) ", %%eax\n" + " movl $" __stringify(CALL32SMM_RETURNID) ", %%ecx\n" + " movl $(1f - " __stringify(BUILD_BIOS_ADDR) "), %%ebx\n" + " outb %%al, $" __stringify(PORT_SMI_CMD) "\n" + " rep; nop\n" + " hlt\n" + + ASM32_SWITCH16 + "1:movl %1, %%eax\n" + " movl %3, %%ecx\n" + " calll _cfunc16_call16_smm_helper\n" + " movl %%eax, %1\n" + + " movl $" __stringify(CALL32SMM_CMDID) ", %%eax\n" + " movl $" __stringify(CALL32SMM_ENTERID) ", %%ecx\n" + " movl $2f, %%ebx\n" + " outb %%al, $" __stringify(PORT_SMI_CMD) "\n" + " rep; nop\n" + " hlt\n" + + // Set esp to flat stack location + ASM32_BACK32 + "2:addl %0, %%esp\n" + : "+r" (stackoffset), "+r" (eax), "+d" (edx) + : "r" (func) + : "eax", "ecx", "ebx", "cc", "memory"); + return eax; +} + +// Backup state in preparation for call32_sloppy() +static void +call32_sloppy_prep(void) +{ + // Backup cmos index register and disable nmi + u8 cmosindex = inb(PORT_CMOS_INDEX); + outb(cmosindex | NMI_DISABLE_BIT, PORT_CMOS_INDEX); + inb(PORT_CMOS_DATA); + SET_LOW(Call32Data.cmosindex, cmosindex); + + // Enable a20 and backup it's previous state + SET_LOW(Call32Data.a20, set_a20(1)); + + // Backup ss/fs/gs and gdt + SET_LOW(Call32Data.ss, GET_SEG(SS)); + SET_LOW(Call32Data.fs, GET_SEG(FS)); + SET_LOW(Call32Data.gs, GET_SEG(GS)); + struct descloc_s gdt; + sgdt(&gdt); + SET_LOW(Call32Data.gdt.length, gdt.length); + SET_LOW(Call32Data.gdt.addr, gdt.addr); + + SET_LOW(Call32Data.method, C32_SLOPPY); +} + +// Restore state backed up during call32_sloppy() +static void +call32_sloppy_post(void) +{ + SET_LOW(Call32Data.method, 0); + SET_LOW(Call32Data.ss, 0); + + // Restore gdt and fs/gs + struct descloc_s gdt; + gdt.length = GET_LOW(Call32Data.gdt.length); + gdt.addr = GET_LOW(Call32Data.gdt.addr); + lgdt(&gdt); + SET_SEG(FS, GET_LOW(Call32Data.fs)); + SET_SEG(GS, GET_LOW(Call32Data.gs)); + + // Restore a20 + set_a20(GET_LOW(Call32Data.a20)); + + // Restore cmos index register + outb(GET_LOW(Call32Data.cmosindex), PORT_CMOS_INDEX); + inb(PORT_CMOS_DATA); +} + +// Call a C function in 32bit mode. This clobbers the 16bit segment +// selector registers. +static u32 +call32_sloppy(void *func, u32 eax) +{ + ASSERT16(); + call32_sloppy_prep(); + u32 bkup_ss, bkup_esp; + asm volatile( + // Backup ss/esp / set esp to flat stack location + " movl %%ss, %0\n" + " movl %%esp, %1\n" + " shll $4, %0\n" + " addl %0, %%esp\n" + " shrl $4, %0\n" + + // Transition to 32bit mode, call func, return to 16bit + " movl $(" __stringify(BUILD_BIOS_ADDR) " + 1f), %%edx\n" + " jmp transition32\n" + ASM16_SWITCH32 + "1:calll *%3\n" + " movl $2f, %%edx\n" + " jmp transition16big\n" + + // Restore ds/ss/esp + ASM16_BACK16 + "2:movl %0, %%ds\n" + " movl %0, %%ss\n" + " movl %1, %%esp\n" + : "=&r" (bkup_ss), "=&r" (bkup_esp), "+a" (eax) + : "r" (func) + : "ecx", "edx", "cc", "memory"); + call32_sloppy_post(); + return eax; +} + +// 16bit handler code called from call16_sloppy() +u32 VISIBLE16 +call16_sloppy_helper(u32 eax, u32 edx, u32 (*func)(u32 eax, u32 edx)) +{ + call32_sloppy_post(); + u32 ret = func(eax, edx); + call32_sloppy_prep(); + return ret; +} + +// Jump back to 16bit mode while in 32bit mode from call32_sloppy() +static u32 +call16_sloppy(u32 eax, u32 edx, void *func) +{ + ASSERT32FLAT(); + if (getesp() > MAIN_STACK_MAX) + panic("call16_sloppy with invalid stack\n"); + func -= BUILD_BIOS_ADDR; + u32 stackseg = Call32Data.ss; + asm volatile( + // Transition to 16bit mode + " movl $(1f - " __stringify(BUILD_BIOS_ADDR) "), %%edx\n" + " jmp transition16big\n" + // Setup ss/esp and call func + ASM32_SWITCH16 + "1:movl %3, %%ecx\n" + " shll $4, %3\n" + " movw %%cx, %%ss\n" + " subl %3, %%esp\n" + " movw %%cx, %%ds\n" + " movl %2, %%edx\n" + " movl %1, %%ecx\n" + " calll _cfunc16_call16_sloppy_helper\n" + // Return to 32bit and restore esp + " movl $2f, %%edx\n" + " jmp transition32\n" + ASM32_BACK32 + "2:addl %3, %%esp\n" + : "+a" (eax) + : "r" (func), "r" (edx), "r" (stackseg) + : "edx", "ecx", "cc", "memory"); + return eax; +} + +// Call a 32bit SeaBIOS function from a 16bit SeaBIOS function. +u32 VISIBLE16 +call32(void *func, u32 eax, u32 errret) +{ + ASSERT16(); + if (CONFIG_CALL32_SMM && GET_GLOBAL(HaveSmmCall32)) + return call32_smm(func, eax); + u32 cr0 = getcr0(); + if (cr0 & CR0_PE) + // Called in 16bit protected mode?! + return errret; + return call32_sloppy(func, eax); +} + +// Call a 16bit SeaBIOS function from a 32bit SeaBIOS function. +static u32 +call16(u32 eax, u32 edx, void *func) +{ + ASSERT32FLAT(); + if (getesp() > BUILD_STACK_ADDR) + panic("call16 with invalid stack\n"); + func -= BUILD_BIOS_ADDR; + asm volatile( + // Transition to 16bit mode + " movl $(1f - " __stringify(BUILD_BIOS_ADDR) "), %%edx\n" + " jmp transition16\n" + // Call func + ASM32_SWITCH16 + "1:movl %2, %%edx\n" + " calll *%1\n" + // Return to 32bit + " movl $2f, %%edx\n" + " jmp transition32\n" + ASM32_BACK32 + "2:\n" + : "+a" (eax) + : "r" (func), "r" (edx) + : "edx", "ecx", "cc", "memory"); + return eax; +} + +// Call a 16bit SeaBIOS function in "big real" mode. +static u32 +call16big(u32 eax, u32 edx, void *func) +{ + ASSERT32FLAT(); + if (getesp() > BUILD_STACK_ADDR) + panic("call16big with invalid stack\n"); + func -= BUILD_BIOS_ADDR; + asm volatile( + // Transition to 16bit mode + " movl $(1f - " __stringify(BUILD_BIOS_ADDR) "), %%edx\n" + " jmp transition16big\n" + // Call func + ASM32_SWITCH16 + "1:movl %2, %%edx\n" + " calll *%1\n" + // Return to 32bit + " movl $2f, %%edx\n" + " jmp transition32\n" + ASM32_BACK32 + "2:\n" + : "+a" (eax) + : "r" (func), "r" (edx) + : "edx", "ecx", "cc", "memory"); + return eax; +} + +// Call a 16bit SeaBIOS function, restoring the mode from last call32(). +static u32 +call16_back(u32 eax, u32 edx, void *func) +{ + ASSERT32FLAT(); + if (CONFIG_CALL32_SMM && Call32Data.method == C32_SMM) + return call16_smm(eax, edx, func); + if (Call32Data.method == C32_SLOPPY) + return call16_sloppy(eax, edx, func); + if (in_post()) + return call16big(eax, edx, func); + return call16(eax, edx, func); +} + + +/**************************************************************** + * Extra 16bit stack + ****************************************************************/ + +// Space for a stack for 16bit code. +u8 ExtraStack[BUILD_EXTRA_STACK_SIZE+1] VARLOW __aligned(8); +u8 *StackPos VARLOW; + +// Test if currently on the extra stack +int +on_extra_stack(void) +{ + return MODE16 && GET_SEG(SS) == SEG_LOW && getesp() > (u32)ExtraStack; +} + +// Switch to the extra stack and call a function. +u32 +stack_hop(u32 eax, u32 edx, void *func) +{ + if (on_extra_stack()) + return ((u32 (*)(u32, u32))func)(eax, edx); + ASSERT16(); + u16 stack_seg = SEG_LOW; + u32 bkup_ss, bkup_esp; + asm volatile( + // Backup current %ss/%esp values. + "movw %%ss, %w3\n" + "movl %%esp, %4\n" + // Copy stack seg to %ds/%ss and set %esp + "movw %w6, %%ds\n" + "movw %w6, %%ss\n" + "movl %5, %%esp\n" + "pushl %3\n" + "pushl %4\n" + // Call func + "calll *%2\n" + "popl %4\n" + "popl %3\n" + // Restore segments and stack + "movw %w3, %%ds\n" + "movw %w3, %%ss\n" + "movl %4, %%esp" + : "+a" (eax), "+d" (edx), "+c" (func), "=&r" (bkup_ss), "=&r" (bkup_esp) + : "m" (StackPos), "r" (stack_seg) + : "cc", "memory"); + return eax; +} + +// Switch back to original caller's stack and call a function. +u32 +stack_hop_back(u32 eax, u32 edx, void *func) +{ + if (!MODESEGMENT) + return call16_back(eax, edx, func); + if (!MODE16 || !on_extra_stack()) + return ((u32 (*)(u32, u32))func)(eax, edx); + ASSERT16(); + u16 bkup_ss; + u32 bkup_stack_pos, temp; + asm volatile( + // Backup stack_pos and current %ss/%esp + "movl %6, %4\n" + "movw %%ss, %w3\n" + "movl %%esp, %6\n" + // Restore original callers' %ss/%esp + "movl -4(%4), %5\n" + "movl %5, %%ss\n" + "movw %%ds:-8(%4), %%sp\n" + "movl %5, %%ds\n" + // Call func + "calll *%2\n" + // Restore %ss/%esp and stack_pos + "movw %w3, %%ds\n" + "movw %w3, %%ss\n" + "movl %6, %%esp\n" + "movl %4, %6" + : "+a" (eax), "+d" (edx), "+c" (func), "=&r" (bkup_ss) + , "=&r" (bkup_stack_pos), "=&r" (temp), "+m" (StackPos) + : + : "cc", "memory"); + return eax; +} + + +/**************************************************************** + * External 16bit interface calling + ****************************************************************/ + +// Far call 16bit code with a specified register state. +void VISIBLE16 +_farcall16(struct bregs *callregs, u16 callregseg) +{ + if (need_hop_back()) { + extern void _cfunc16__farcall16(void); + stack_hop_back((u32)callregs, callregseg, _cfunc16__farcall16); + return; + } + ASSERT16(); + asm volatile( + "calll __farcall16\n" + : "+a" (callregs), "+m" (*callregs), "+d" (callregseg) + : + : "ebx", "ecx", "esi", "edi", "cc", "memory"); +} + +void +farcall16(struct bregs *callregs) +{ + extern void _cfunc16__farcall16(void); + call16((u32)callregs, 0, _cfunc16__farcall16); +} + +void +farcall16big(struct bregs *callregs) +{ + extern void _cfunc16__farcall16(void); + call16big((u32)callregs, 0, _cfunc16__farcall16); +} + +// Invoke a 16bit software interrupt. +void +__call16_int(struct bregs *callregs, u16 offset) +{ + callregs->code.offset = offset; + if (!MODESEGMENT) { + callregs->code.seg = SEG_BIOS; + _farcall16((void*)callregs - Call32Data.ss * 16, Call32Data.ss); + return; + } + callregs->code.seg = GET_SEG(CS); + _farcall16(callregs, GET_SEG(SS)); +} + +// Reset the machine +void +reset(void) +{ + extern void reset_vector(void) __noreturn; + if (!MODE16) + call16_back(0, 0, reset_vector); + reset_vector(); +} + + +/**************************************************************** + * Threads + ****************************************************************/ + +// Thread info - stored at bottom of each thread stack - don't change +// without also updating the inline assembler below. +struct thread_info { + void *stackpos; + struct hlist_node node; +}; +struct thread_info MainThread VARFSEG = { + NULL, { &MainThread.node, &MainThread.node.next } +}; +#define THREADSTACKSIZE 4096 + +// Check if any threads are running. +static int +have_threads(void) +{ + return (CONFIG_THREADS + && GET_FLATPTR(MainThread.node.next) != &MainThread.node); +} + +// Return the 'struct thread_info' for the currently running thread. +struct thread_info * +getCurThread(void) +{ + u32 esp = getesp(); + if (esp <= MAIN_STACK_MAX) + return &MainThread; + return (void*)ALIGN_DOWN(esp, THREADSTACKSIZE); +} + +static int ThreadControl; + +// Initialize the support for internal threads. +void +thread_init(void) +{ + if (! CONFIG_THREADS) + return; + ThreadControl = romfile_loadint("etc/threads", 1); +} + +// Should hardware initialization threads run during optionrom execution. +int +threads_during_optionroms(void) +{ + return CONFIG_THREADS && ThreadControl == 2 && in_post(); +} + +// Switch to next thread stack. +static void +switch_next(struct thread_info *cur) +{ + struct thread_info *next = container_of( + cur->node.next, struct thread_info, node); + if (cur == next) + // Nothing to do. + return; + asm volatile( + " pushl $1f\n" // store return pc + " pushl %%ebp\n" // backup %ebp + " movl %%esp, (%%eax)\n" // cur->stackpos = %esp + " movl (%%ecx), %%esp\n" // %esp = next->stackpos + " popl %%ebp\n" // restore %ebp + " retl\n" // restore pc + "1:\n" + : "+a"(cur), "+c"(next) + : + : "ebx", "edx", "esi", "edi", "cc", "memory"); +} + +// Last thing called from a thread (called on MainThread stack). +static void +__end_thread(struct thread_info *old) +{ + hlist_del(&old->node); + dprintf(DEBUG_thread, "\\%08x/ End thread\n", (u32)old); + free(old); + if (!have_threads()) + dprintf(1, "All threads complete.\n"); +} + +// Create a new thread and start executing 'func' in it. +void +run_thread(void (*func)(void*), void *data) +{ + ASSERT32FLAT(); + if (! CONFIG_THREADS || ! ThreadControl) + goto fail; + struct thread_info *thread; + thread = memalign_tmphigh(THREADSTACKSIZE, THREADSTACKSIZE); + if (!thread) + goto fail; + + dprintf(DEBUG_thread, "/%08x\\ Start thread\n", (u32)thread); + thread->stackpos = (void*)thread + THREADSTACKSIZE; + struct thread_info *cur = getCurThread(); + hlist_add_after(&thread->node, &cur->node); + asm volatile( + // Start thread + " pushl $1f\n" // store return pc + " pushl %%ebp\n" // backup %ebp + " movl %%esp, (%%edx)\n" // cur->stackpos = %esp + " movl (%%ebx), %%esp\n" // %esp = thread->stackpos + " calll *%%ecx\n" // Call func + + // End thread + " movl %%ebx, %%eax\n" // %eax = thread + " movl 4(%%ebx), %%ebx\n" // %ebx = thread->node.next + " movl (%5), %%esp\n" // %esp = MainThread.stackpos + " calll %4\n" // call __end_thread(thread) + " movl -4(%%ebx), %%esp\n" // %esp = next->stackpos + " popl %%ebp\n" // restore %ebp + " retl\n" // restore pc + "1:\n" + : "+a"(data), "+c"(func), "+b"(thread), "+d"(cur) + : "m"(*(u8*)__end_thread), "m"(MainThread) + : "esi", "edi", "cc", "memory"); + return; + +fail: + func(data); +} + + +/**************************************************************** + * Thread helpers + ****************************************************************/ + +// Low-level irq enable. +void VISIBLE16 +check_irqs(void) +{ + if (need_hop_back()) { + extern void _cfunc16_check_irqs(void); + stack_hop_back(0, 0, _cfunc16_check_irqs); + return; + } + asm volatile("sti ; nop ; rep ; nop ; cli ; cld" : : :"memory"); +} + +// Briefly permit irqs to occur. +void +yield(void) +{ + if (MODESEGMENT || !CONFIG_THREADS) { + check_irqs(); + return; + } + struct thread_info *cur = getCurThread(); + if (cur == &MainThread) + // Permit irqs to fire + check_irqs(); + + // Switch to the next thread + switch_next(cur); +} + +void VISIBLE16 +wait_irq(void) +{ + if (need_hop_back()) { + extern void _cfunc16_wait_irq(void); + stack_hop_back(0, 0, _cfunc16_wait_irq); + return; + } + asm volatile("sti ; hlt ; cli ; cld": : :"memory"); +} + +// Wait for next irq to occur. +void +yield_toirq(void) +{ + if (!MODESEGMENT && have_threads()) { + // Threads still active - do a yield instead. + yield(); + return; + } + wait_irq(); +} + +// Wait for all threads (other than the main thread) to complete. +void +wait_threads(void) +{ + ASSERT32FLAT(); + while (have_threads()) + yield(); +} + +void +mutex_lock(struct mutex_s *mutex) +{ + ASSERT32FLAT(); + if (! CONFIG_THREADS) + return; + while (mutex->isLocked) + yield(); + mutex->isLocked = 1; +} + +void +mutex_unlock(struct mutex_s *mutex) +{ + ASSERT32FLAT(); + if (! CONFIG_THREADS) + return; + mutex->isLocked = 0; +} + + +/**************************************************************** + * Thread preemption + ****************************************************************/ + +int CanPreempt VARFSEG; +static u32 PreemptCount; + +// Turn on RTC irqs and arrange for them to check the 32bit threads. +void +start_preempt(void) +{ + if (! threads_during_optionroms()) + return; + CanPreempt = 1; + PreemptCount = 0; + rtc_use(); +} + +// Turn off RTC irqs / stop checking for thread execution. +void +finish_preempt(void) +{ + if (! threads_during_optionroms()) { + yield(); + return; + } + CanPreempt = 0; + rtc_release(); + dprintf(9, "Done preempt - %d checks\n", PreemptCount); + yield(); +} + +// Check if preemption is on, and wait for it to complete if so. +int +wait_preempt(void) +{ + if (MODESEGMENT || !CONFIG_THREADS || !CanPreempt + || getesp() < MAIN_STACK_MAX) + return 0; + while (CanPreempt) + yield(); + return 1; +} + +// Try to execute 32bit threads. +void VISIBLE32INIT +yield_preempt(void) +{ + PreemptCount++; + switch_next(&MainThread); +} + +// 16bit code that checks if threads are pending and executes them if so. +void +check_preempt(void) +{ + extern void _cfunc32flat_yield_preempt(void); + if (CONFIG_THREADS && GET_GLOBAL(CanPreempt) && have_threads()) + call32(_cfunc32flat_yield_preempt, 0, 0); +} + + +/**************************************************************** + * call32 helper + ****************************************************************/ + +struct call32_params_s { + void *func; + u32 eax, edx, ecx; +}; + +u32 VISIBLE32FLAT +call32_params_helper(struct call32_params_s *params) +{ + return ((u32 (*)(u32, u32, u32))params->func)( + params->eax, params->edx, params->ecx); +} + +u32 +call32_params(void *func, u32 eax, u32 edx, u32 ecx, u32 errret) +{ + ASSERT16(); + struct call32_params_s params = {func, eax, edx, ecx}; + extern void _cfunc32flat_call32_params_helper(void); + return call32(_cfunc32flat_call32_params_helper + , (u32)MAKE_FLATPTR(GET_SEG(SS), ¶ms), errret); +} |