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After queuing a SEGV for the process that caused a page fault, we call the scheduler to properly handle it.

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This commit is contained in:
Enrico Fraccaroli (Galfurian)
2023-08-22 15:40:05 -04:00
parent bf59ccd0f4
commit c82779f1af
1 changed files with 23 additions and 8 deletions
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mentos/src/mem/paging.c
+23 -8
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@@ -4,10 +4,10 @@
/// See LICENSE.md for details.
// Setup the logging for this file (do this before any other include).
#include "sys/kernel_levels.h" // Include kernel log levels.
#define __DEBUG_HEADER__ "[PAGING]" ///< Change header.
#define __DEBUG_LEVEL__ LOGLEVEL_NOTICE ///< Set log level.
#include "io/debug.h" // Include debugging functions.
#include "sys/kernel_levels.h" // Include kernel log levels.
#define __DEBUG_HEADER__ "[PAGING]" ///< Change header.
#define __DEBUG_LEVEL__ LOGLEVEL_DEBUG ///< Set log level.
#include "io/debug.h" // Include debugging functions.
#include "mem/paging.h"
#include "mem/vmem_map.h"
@@ -458,20 +458,27 @@ void page_fault_handler(pt_regs *f)
// Get the directory entry.
page_dir_entry_t *direntry = &lowmem_dir->entries[faulting_addr / (1024U * PAGE_SIZE)];
// Extract the error
bool_t err_user = bit_check(f->err_code, 2);
bool_t err_rw = bit_check(f->err_code, 1);
bool_t err_present = bit_check(f->err_code, 0);
bool_t err_user = bit_check(f->err_code, 2) != 0;
bool_t err_rw = bit_check(f->err_code, 1) != 0;
bool_t err_present = bit_check(f->err_code, 0) != 0;
// Panic only if page is in kernel memory, else abort process with SIGSEGV.
if (!direntry->present) {
pr_crit("ERR(0): %d%d%d\n", err_user, err_rw, err_present);
if (err_user) {
// Get the current process.
task_struct *task = scheduler_get_current_process();
if (task) {
// Notifies current process.
sys_kill(task->pid, SIGSEGV);
// Now, we know the process needs to be removed from the list of
// running processes. We pushed the SEGV signal in the queues of
// signal to send to the process. To properly handle the signal,
// just run scheduler.
scheduler_run(f);
return;
}
}
pr_crit("ERR(0): So, it is not present, and it was not the user.\n");
__page_fault_panic(f, faulting_addr);
}
// Get the physical address of the page table.
@@ -489,6 +496,7 @@ void page_fault_handler(pt_regs *f)
page_table_entry_t *orig_entry = (page_table_entry_t *)(*(uint32_t *)entry);
// Check if the page is Copy on Write (CoW).
if (__page_handle_cow(orig_entry)) {
pr_crit("ERR(1): %d%d%d\n", err_user, err_rw, err_present);
__page_fault_panic(f, faulting_addr);
}
// Update the page table entry frame.
@@ -498,16 +506,23 @@ void page_fault_handler(pt_regs *f)
} else {
// Check if the page is Copy on Write (CoW).
if (__page_handle_cow(entry)) {
pr_crit("ERR(2): %d%d%d\n", err_user, err_rw, err_present);
if (err_user && err_rw && err_present) {
// Get the current process.
task_struct *task = scheduler_get_current_process();
if (task) {
// Notifies current process.
sys_kill(task->pid, SIGSEGV);
// Now, we know the process needs to be removed from the list of
// running processes. We pushed the SEGV signal in the queues of
// signal to send to the process. To properly handle the signal,
// just run scheduler.
scheduler_run(f);
return;
}
pr_crit("ERR(2): There is no task.\n");
}
pr_crit("ERR(2): We continued...\n");
__page_fault_panic(f, faulting_addr);
}
}