[SeaBIOS] [PATCH 1/4] Allow wait_irq to be called in 32bit code.
Kevin O'Connor
kevin at koconnor.net
Sun May 23 22:16:26 CEST 2010
If wait_irq() is called from 32bit code, then jump to 16bit mode for
the wait.
Have wait_irq check for threads, and have it use yield if threads are
pending. This ensures threads aren't delayed if anything calls
wait_irq.
Use wait_irq() in 32bit mode during a failed boot.
---
Makefile | 2 +-
src/boot.c | 2 +-
src/stacks.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
src/util.c | 29 --------------------
src/util.h | 14 +++-------
5 files changed, 79 insertions(+), 51 deletions(-)
diff --git a/Makefile b/Makefile
index d0b8881..72d711d 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@ SRC16=$(SRCBOTH) system.c disk.c apm.c font.c
SRC32FLAT=$(SRCBOTH) post.c shadow.c memmap.c coreboot.c boot.c \
acpi.c smm.c mptable.c smbios.c pciinit.c optionroms.c mtrr.c \
lzmadecode.c usb-hub.c paravirt.c
-SRC32SEG=util.c output.c pci.c pcibios.c apm.c
+SRC32SEG=util.c output.c pci.c pcibios.c apm.c stacks.c
cc-option = $(shell if test -z "`$(1) $(2) -S -o /dev/null -xc \
/dev/null 2>&1`"; then echo "$(2)"; else echo "$(3)"; fi ;)
diff --git a/src/boot.c b/src/boot.c
index 36450f0..335522f 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -449,7 +449,7 @@ do_boot(u16 seq_nr)
printf("No bootable device.\n");
// Loop with irqs enabled - this allows ctrl+alt+delete to work.
for (;;)
- biosusleep(1000000);
+ wait_irq();
}
/* Do the loading, and set up vector as a far pointer to the boot
diff --git a/src/stacks.c b/src/stacks.c
index 859de3f..f5feeeb 100644
--- a/src/stacks.c
+++ b/src/stacks.c
@@ -8,6 +8,20 @@
#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 VAR16VISIBLE MainThread;
+
+
+/****************************************************************
+ * Low level helpers
+ ****************************************************************/
+
static inline u32 getcr0(void) {
u32 cr0;
asm("movl %%cr0, %0" : "=r"(cr0));
@@ -77,6 +91,65 @@ call32(void *func)
return 0;
}
+// 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;
+ call16big(&br);
+}
+
+// 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
+wait_irq(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;
+ call16big(&br);
+}
+
/****************************************************************
* Stack in EBDA
@@ -115,16 +188,6 @@ stack_hop(u32 eax, u32 edx, void *func)
****************************************************************/
#define THREADSTACKSIZE 4096
-
-// 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 VAR16VISIBLE MainThread;
int VAR16VISIBLE CanPreempt;
void
diff --git a/src/util.c b/src/util.c
index e146c97..b078d5f 100644
--- a/src/util.c
+++ b/src/util.c
@@ -57,35 +57,6 @@ __call16_int(struct bregs *callregs, u16 offset)
call16(callregs);
}
-// 16bit trampoline for enabling irqs from 32bit mode.
-ASM16(
- " .global trampoline_checkirqs\n"
- "trampoline_checkirqs:\n"
- " rep ; nop\n"
- " lretw"
- );
-
-void
-check_irqs(void)
-{
- if (MODE16) {
- asm volatile(
- "sti\n"
- "nop\n"
- "rep ; nop\n"
- "cli\n"
- "cld\n"
- : : :"memory");
- } else {
- extern void trampoline_checkirqs();
- struct bregs br;
- br.flags = F_IF;
- br.code.seg = SEG_BIOS;
- br.code.offset = (u32)&trampoline_checkirqs;
- call16big(&br);
- }
-}
-
/****************************************************************
* String ops
diff --git a/src/util.h b/src/util.h
index e47860f..a5c5b75 100644
--- a/src/util.h
+++ b/src/util.h
@@ -21,7 +21,7 @@ static inline void irq_enable(void)
static inline unsigned long irq_save(void)
{
unsigned long flags;
- asm volatile("pushfl ; popl %0" : "=g" (flags));
+ asm volatile("pushfl ; popl %0" : "=g" (flags): :"memory");
irq_disable();
return flags;
}
@@ -36,12 +36,6 @@ static inline void cpu_relax(void)
asm volatile("rep ; nop": : :"memory");
}
-// Atomically enable irqs and sleep until an irq; then re-disable irqs.
-static inline void wait_irq(void)
-{
- asm volatile("sti ; hlt ; cli ; cld": : :"memory");
-}
-
static inline void nop(void)
{
asm volatile("nop");
@@ -49,12 +43,12 @@ static inline void nop(void)
static inline void hlt(void)
{
- asm volatile("hlt");
+ asm volatile("hlt": : :"memory");
}
static inline void wbinvd(void)
{
- asm volatile("wbinvd");
+ asm volatile("wbinvd": : :"memory");
}
#define CPUID_MSR (1 << 5)
@@ -182,7 +176,6 @@ inline void __call16_int(struct bregs *callregs, u16 offset);
extern void irq_trampoline_ ##nr (); \
__call16_int((callregs), (u32)&irq_trampoline_ ##nr ); \
} while (0)
-void check_irqs(void);
u8 checksum_far(u16 buf_seg, void *buf_far, u32 len);
u8 checksum(void *buf, u32 len);
size_t strlen(const char *s);
@@ -209,6 +202,7 @@ extern struct thread_info MainThread;
void thread_setup(void);
struct thread_info *getCurThread(void);
void yield(void);
+void wait_irq(void);
void run_thread(void (*func)(void*), void *data);
void wait_threads(void);
struct mutex_s { u32 isLocked; };
--
1.6.6.1
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