diff options
| -rw-r--r-- | src/stacks.c | 237 | ||||
| -rw-r--r-- | src/util.c | 49 | ||||
| -rw-r--r-- | src/util.h | 20 |
3 files changed, 150 insertions, 156 deletions
diff --git a/src/stacks.c b/src/stacks.c index 48512b0..da5daa9 100644 --- a/src/stacks.c +++ b/src/stacks.c @@ -8,20 +8,44 @@ #include "util.h" // dprintf #include "bregs.h" // CR0_PE -// Thread info - stored at bottom of each thread stack - don't change -// without also updating the inline assembler below. -struct thread_info { - struct thread_info *next; - void *stackpos; - struct thread_info **pprev; -}; -struct thread_info VAR32FLATVISIBLE MainThread = { - &MainThread, NULL, &MainThread.next -}; + +/**************************************************************** + * Extra 16bit stack + ****************************************************************/ + +// Space for a stack for 16bit code. +u8 ExtraStack[BUILD_EXTRA_STACK_SIZE+1] VARLOW __aligned(8); + +// Switch to the extra stack and call a function. +inline u32 +stack_hop(u32 eax, u32 edx, void *func) +{ + ASSERT16(); + u16 stack_seg = SEG_LOW, bkup_ss; + u32 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" + // Call func + "calll *%2\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) + : "i" (&ExtraStack[BUILD_EXTRA_STACK_SIZE]), "r" (stack_seg) + : "cc", "memory"); + return eax; +} /**************************************************************** - * Low level helpers + * 16bit / 32bit calling ****************************************************************/ static inline void sgdt(struct descloc_s *desc) { @@ -88,98 +112,48 @@ call32(void *func, u32 eax, u32 errret) return eax; } -// 16bit trampoline for enabling irqs from 32bit mode. -ASM16( - " .global trampoline_checkirqs\n" - "trampoline_checkirqs:\n" - " rep ; nop\n" - " lretw" - ); - -static void -check_irqs(void) +// Call a function with a specified register state. Note that on +// return, the interrupt enable/disable flag may be altered. +inline void +farcall16(struct bregs *callregs) { - if (MODESEGMENT) { - asm volatile( - "sti\n" - "nop\n" - "rep ; nop\n" - "cli\n" - "cld\n" - : : :"memory"); - return; - } - extern void trampoline_checkirqs(); - struct bregs br; - br.flags = F_IF; - br.code.seg = SEG_BIOS; - br.code.offset = (u32)&trampoline_checkirqs; - farcall16big(&br); + if (!MODESEGMENT && getesp() > BUILD_STACK_ADDR) + panic("call16 with invalid stack\n"); + asm volatile( +#if MODE16 == 1 + "calll __farcall16\n" + "cli\n" + "cld" +#else + "calll __farcall16_from32" +#endif + : "+a" (callregs), "+m" (*callregs) + : + : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory"); } -// 16bit trampoline for waiting for an irq from 32bit mode. -ASM16( - " .global trampoline_waitirq\n" - "trampoline_waitirq:\n" - " sti\n" - " hlt\n" - " lretw" - ); - -// Wait for next irq to occur. -void -yield_toirq(void) +inline void +farcall16big(struct bregs *callregs) { - if (MODESEGMENT) { - asm volatile("sti ; hlt ; cli ; cld": : :"memory"); - return; - } - if (CONFIG_THREADS && MainThread.next != &MainThread) { - // Threads still active - do a yield instead. - yield(); - return; - } - extern void trampoline_waitirq(); - struct bregs br; - br.flags = 0; - br.code.seg = SEG_BIOS; - br.code.offset = (u32)&trampoline_waitirq; - farcall16big(&br); + ASSERT32FLAT(); + if (getesp() > BUILD_STACK_ADDR) + panic("call16 with invalid stack\n"); + asm volatile( + "calll __farcall16big_from32" + : "+a" (callregs), "+m" (*callregs) + : + : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory"); } - -/**************************************************************** - * Extra 16bit stack - ****************************************************************/ - -// Space for a stack for 16bit code. -u8 ExtraStack[BUILD_EXTRA_STACK_SIZE+1] VARLOW __aligned(8); - -// Switch to the extra stack and call a function. -inline u32 -stack_hop(u32 eax, u32 edx, void *func) +inline void +__call16_int(struct bregs *callregs, u16 offset) { - ASSERT16(); - u16 stack_seg = SEG_LOW, bkup_ss; - u32 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" - // Call func - "calll *%2\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) - : "i" (&ExtraStack[BUILD_EXTRA_STACK_SIZE]), "r" (stack_seg) - : "cc", "memory"); - return eax; + if (MODESEGMENT) + callregs->code.seg = GET_SEG(CS); + else + callregs->code.seg = SEG_BIOS; + callregs->code.offset = offset; + farcall16(callregs); } @@ -187,8 +161,17 @@ stack_hop(u32 eax, u32 edx, void *func) * Threads ****************************************************************/ +// Thread info - stored at bottom of each thread stack - don't change +// without also updating the inline assembler below. +struct thread_info { + struct thread_info *next; + void *stackpos; + struct thread_info **pprev; +}; +struct thread_info VAR32FLATVISIBLE MainThread = { + &MainThread, NULL, &MainThread.next +}; #define THREADSTACKSIZE 4096 -int VAR16VISIBLE CanPreempt; // Return the 'struct thread_info' for the currently running thread. struct thread_info * @@ -221,6 +204,35 @@ switch_next(struct thread_info *cur) : "ebx", "edx", "esi", "edi", "cc", "memory"); } +// 16bit trampoline for enabling irqs from 32bit mode. +ASM16( + " .global trampoline_checkirqs\n" + "trampoline_checkirqs:\n" + " rep ; nop\n" + " lretw" + ); + +static void +check_irqs(void) +{ + if (MODESEGMENT) { + asm volatile( + "sti\n" + "nop\n" + "rep ; nop\n" + "cli\n" + "cld\n" + : : :"memory"); + return; + } + extern void trampoline_checkirqs(); + struct bregs br; + br.flags = F_IF; + br.code.seg = SEG_BIOS; + br.code.offset = (u32)&trampoline_checkirqs; + farcall16big(&br); +} + // Briefly permit irqs to occur. void yield(void) @@ -239,6 +251,36 @@ yield(void) switch_next(cur); } +// 16bit trampoline for waiting for an irq from 32bit mode. +ASM16( + " .global trampoline_waitirq\n" + "trampoline_waitirq:\n" + " sti\n" + " hlt\n" + " lretw" + ); + +// Wait for next irq to occur. +void +yield_toirq(void) +{ + if (MODESEGMENT) { + asm volatile("sti ; hlt ; cli ; cld": : :"memory"); + return; + } + if (CONFIG_THREADS && MainThread.next != &MainThread) { + // Threads still active - do a yield instead. + yield(); + return; + } + extern void trampoline_waitirq(); + struct bregs br; + br.flags = 0; + br.code.seg = SEG_BIOS; + br.code.offset = (u32)&trampoline_waitirq; + farcall16big(&br); +} + // Last thing called from a thread (called on "next" stack). static void __end_thread(struct thread_info *old) @@ -332,6 +374,7 @@ mutex_unlock(struct mutex_s *mutex) * Thread preemption ****************************************************************/ +int VAR16VISIBLE CanPreempt; static u32 PreemptCount; // Turn on RTC irqs and arrange for them to check the 32bit threads. @@ -26,55 +26,6 @@ cpuid(u32 index, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx) /**************************************************************** - * 16bit calls - ****************************************************************/ - -// Call a function with a specified register state. Note that on -// return, the interrupt enable/disable flag may be altered. -inline void -farcall16(struct bregs *callregs) -{ - if (!MODESEGMENT && getesp() > BUILD_STACK_ADDR) - panic("call16 with invalid stack\n"); - asm volatile( -#if MODE16 == 1 - "calll __farcall16\n" - "cli\n" - "cld" -#else - "calll __farcall16_from32" -#endif - : "+a" (callregs), "+m" (*callregs) - : - : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory"); -} - -inline void -farcall16big(struct bregs *callregs) -{ - ASSERT32FLAT(); - if (getesp() > BUILD_STACK_ADDR) - panic("call16 with invalid stack\n"); - asm volatile( - "calll __farcall16big_from32" - : "+a" (callregs), "+m" (*callregs) - : - : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory"); -} - -inline void -__call16_int(struct bregs *callregs, u16 offset) -{ - if (MODESEGMENT) - callregs->code.seg = GET_SEG(CS); - else - callregs->code.seg = SEG_BIOS; - callregs->code.offset = offset; - farcall16(callregs); -} - - -/**************************************************************** * String ops ****************************************************************/ @@ -197,14 +197,6 @@ struct descloc_s { // util.c void cpuid(u32 index, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx); -struct bregs; -inline void farcall16(struct bregs *callregs); -inline void farcall16big(struct bregs *callregs); -inline void __call16_int(struct bregs *callregs, u16 offset); -#define call16_int(nr, callregs) do { \ - extern void irq_trampoline_ ##nr (); \ - __call16_int((callregs), (u32)&irq_trampoline_ ##nr ); \ - } while (0) u8 checksum_far(u16 buf_seg, void *buf_far, u32 len); u8 checksum(void *buf, u32 len); size_t strlen(const char *s); @@ -229,11 +221,18 @@ void nullTrailingSpace(char *buf); int get_keystroke(int msec); // stacks.c -u32 call32(void *func, u32 eax, u32 errret); extern u8 ExtraStack[]; inline u32 stack_hop(u32 eax, u32 edx, void *func); +u32 call32(void *func, u32 eax, u32 errret); +struct bregs; +inline void farcall16(struct bregs *callregs); +inline void farcall16big(struct bregs *callregs); +inline void __call16_int(struct bregs *callregs, u16 offset); +#define call16_int(nr, callregs) do { \ + extern void irq_trampoline_ ##nr (); \ + __call16_int((callregs), (u32)&irq_trampoline_ ##nr ); \ + } while (0) extern struct thread_info MainThread; -extern int CanPreempt; struct thread_info *getCurThread(void); void yield(void); void yield_toirq(void); @@ -242,6 +241,7 @@ void wait_threads(void); struct mutex_s { u32 isLocked; }; void mutex_lock(struct mutex_s *mutex); void mutex_unlock(struct mutex_s *mutex); +extern int CanPreempt; void start_preempt(void); void finish_preempt(void); int wait_preempt(void); |