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allocate stacks on demand, reduce the size of the BSS section

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Stefan Lankes 2017-11-04 12:46:57 +01:00
parent 968e989970
commit 4c8e066aae
3 changed files with 39 additions and 17 deletions
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26
arch/x86/include/asm/gdt.h
View file

@ -51,26 +51,26 @@ extern "C" {
#define GDT_FLAG_TSS_BUSY 0x02
#define GDT_FLAG_SEGMENT 0x10
/// Privilege level: Ring 0
/// Privilege level: Ring 0
#define GDT_FLAG_RING0 0x00
/// Privilege level: Ring 1
#define GDT_FLAG_RING1 0x20
/// Privilege level: Ring 2
/// Privilege level: Ring 2
#define GDT_FLAG_RING2 0x40
/// Privilege level: Ring 3
/// Privilege level: Ring 3
#define GDT_FLAG_RING3 0x60
/// Segment is present
#define GDT_FLAG_PRESENT 0x80
/// Segment was accessed
#define GDT_FLAG_ACCESSED 0x01
/**
* @brief Granularity of segment limit
/**
* @brief Granularity of segment limit
* - set: segment limit unit is 4 KB (page size)
* - not set: unit is bytes
*/
#define GDT_FLAG_4K_GRAN 0x80
/**
* @brief Default operand size
* @brief Default operand size
* - set: 32 bit
* - not set: 16 bit
*/
@ -78,7 +78,7 @@ extern "C" {
#define GDT_FLAG_32_BIT 0x40
#define GDT_FLAG_64_BIT 0x20
/** @brief Defines a GDT entry
/** @brief Defines a GDT entry
*
* A global descriptor table entry consists of:
* - 32 bit base address (chunkwise embedded into this structure)
@ -115,16 +115,16 @@ typedef struct {
#if GDT_ENTRIES > 8192
#error Too many GDT entries!
#endif
#endif
/** @brief Installs the global descriptor table
*
* The installation involves the following steps:
* - set up the special GDT pointer
* - set up the special GDT pointer
* - set up the entries in our GDT
* - finally call gdt_flush() in our assembler file
* - finally call gdt_flush() in our assembler file
* in order to tell the processor where the new GDT is
* - update the new segment registers
* - update the new segment registers
*/
void gdt_install(void);
@ -143,6 +143,10 @@ void gdt_set_gate(int num, unsigned long base, unsigned long limit,
void configure_gdt_entry(gdt_entry_t *dest_entry, unsigned long base, unsigned long limit,
unsigned char access, unsigned char gran);
/** @brief Initialize the task state segments
*/
void tss_init(void);
#ifdef __cplusplus
}
#endif

27
arch/x86/kernel/gdt.c
View file

@ -31,6 +31,7 @@
#include <hermit/tasks.h>
#include <hermit/errno.h>
#include <hermit/processor.h>
#include <hermit/logging.h>
#include <asm/gdt.h>
#include <asm/tss.h>
#include <asm/page.h>
@ -41,7 +42,6 @@ gdt_ptr_t gp;
// currently, our kernel has full access to the ioports
static gdt_entry_t gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0, 0}};
static tss_t task_state_segments[MAX_CORES] __attribute__ ((aligned (PAGE_SIZE)));
static uint8_t stack_table[MAX_CORES][KERNEL_STACK_SIZE*MAX_IST] __attribute__ ((aligned (PAGE_SIZE)));
extern const void boot_stack;
@ -94,7 +94,8 @@ void gdt_install(void)
{
int i, num = 0;
memset(task_state_segments, 0x00, MAX_CORES*sizeof(tss_t));
// part of bss => already initialized
//memset(task_state_segments, 0x00, MAX_CORES*sizeof(tss_t));
/* Setup the GDT pointer and limit */
gp.limit = (sizeof(gdt_entry_t) * GDT_ENTRIES) - 1;
@ -148,10 +149,6 @@ void gdt_install(void)
*/
for(i=0; i<MAX_CORES; i++) {
task_state_segments[i].rsp0 = (size_t)&boot_stack + (i+1) * KERNEL_STACK_SIZE - 0x10;
task_state_segments[i].ist1 = 0; // ist will created per task
task_state_segments[i].ist2 = (size_t) stack_table[i] + (2 /*IST number */ - 1) * KERNEL_STACK_SIZE - 0x10;
task_state_segments[i].ist3 = (size_t) stack_table[i] + (3 /*IST number */ - 1) * KERNEL_STACK_SIZE - 0x10;
task_state_segments[i].ist4 = (size_t) stack_table[i] + (4 /*IST number */ - 1) * KERNEL_STACK_SIZE - 0x10;
gdt_set_gate(num+i*2, (unsigned long) (task_state_segments+i), sizeof(tss_t),
GDT_FLAG_PRESENT | GDT_FLAG_TSS | GDT_FLAG_RING0, 0);
@ -160,3 +157,21 @@ void gdt_install(void)
/* Flush out the old GDT and install the new changes! */
gdt_flush();
}
void tss_init(void)
{
LOG_INFO("Initialized the task state segments\n");
for(int i=0; i<MAX_CORES; i++) {
if (task_state_segments[i].ist1 == 0)
task_state_segments[i].ist1 = (size_t) create_stack(KERNEL_STACK_SIZE) + KERNEL_STACK_SIZE - 0x10;
if (task_state_segments[i].ist2 == 0)
task_state_segments[i].ist2 = (size_t) create_stack(KERNEL_STACK_SIZE) + KERNEL_STACK_SIZE - 0x10;
if (task_state_segments[i].ist2 == 0)
task_state_segments[i].ist2 = (size_t) create_stack(KERNEL_STACK_SIZE) + KERNEL_STACK_SIZE - 0x10;
if (task_state_segments[i].ist3 == 0)
task_state_segments[i].ist3 = (size_t) create_stack(KERNEL_STACK_SIZE) + KERNEL_STACK_SIZE - 0x10;
if (task_state_segments[i].ist4 == 0)
task_state_segments[i].ist4 = (size_t) create_stack(KERNEL_STACK_SIZE) + KERNEL_STACK_SIZE - 0x10;
}
}

3
arch/x86/mm/memory.c
View file

@ -361,6 +361,9 @@ int memory_init(void)
}
}
// Ok, we are now able to use our memory management => update tss
tss_init();
return ret;
oom: