hide needlessly exported symbols

4 files changed, 89 insertions, 14 deletions

diff --git a/kc/component.ld b/kc/component.ld
index 3a48ae8..dc158f3 100644
--- a/kc/component.ld
+++ b/kc/component.ld
@@ -2,7 +2,7 @@ ENTRY(kc_entry)
 
 SECTIONS
 {
-    PROVIDE(kc_image_base = .);
+    PROVIDE_HIDDEN(kc_image_base = .);
 
     . = sizeof_headers;
 
diff --git a/kc/core/cpu/cpu_task.S b/kc/core/cpu/cpu_task.S
new file mode 100644
index 0000000..f2fb473
--- /dev/null
+++ b/kc/core/cpu/cpu_task.S
@@ -0,0 +1,45 @@
+/* thread switching routines for x86_64
+* adapted from:
+* https://wiki.osdev.org/Brendan%27s_Multi-tasking_Tutorial
+* 
+* 
+*/
+
+.hidden cpu_set_thread
+.global cpu_set_thread
+.type cpu_set_thread, @function
+cpu_set_thread:
+    /* x86_64 SysV ABI
+    *  must save the following registers to the stack:
+    *   rbx, rsp, rbp, r12, r13, r14, r15
+    *  the following are the parameters for switching tasks
+    *   rdi: pointer to control block of thread being switched to 
+    *   rsi: pointer to control block of the current thread
+    *   rdx: pointer to this cpu's task state segment esp0 field
+    */
+    push %rbx
+    push %r12
+    push %r13
+    push %r14
+    push %r15
+    push %rbp
+    /* the current task will be in rsi */
+    mov %esp, 0(%rsi) // save the stack pointer for the current task
+    mov 0(%rdi),%rsp // new stack is the next's task's stack
+    mov 8(%rdi),%rbx // top of the next task's kernel stack
+    mov %rbx,0(%rdx) // save the esp0 to the tss
+    mov 16(%rdi),%rax // page map for the next task
+    mov %cr3, %rcx // in case we need to change the page map
+    cmp %rax,%rcx
+    je .Lfinish
+    mov %rax,%cr3 // if the page maps are not the same, reload
+.Lfinish:
+    pop %rbp // get all the registers off the new task's stack
+    pop %r15
+    pop %r14
+    pop %r13
+    pop %r12
+    pop %rbx
+    ret // leave into the new task
+.size cpu_set_thread, . - cpu_set_thread
+
diff --git a/kc/core/exceptions.S b/kc/core/exceptions.S
index 80d49ee..46b9947 100644
--- a/kc/core/exceptions.S
+++ b/kc/core/exceptions.S
@@ -1,8 +1,7 @@
 .extern page_fault_handler
+.extern general_protection_handler
 
-.global page_fault_isr
-.type page_fault_isr, @function
-page_fault_isr:
+.macro ISR_STORE_REGISTERS
     /* just in case something tried to be clever before */
     cld
     /* push param registers */
@@ -12,9 +11,6 @@ page_fault_isr:
     push %rcx
     push %r8
     push %r9
-    /* collect parameters for page fault handler */
-    mov 48(%rsp), %rdi /* error code is first parameter */
-    mov %cr2, %rsi /* PFLA is next parameter */
     /* caller-saved registers */
     push %rax
     push %r10
@@ -26,13 +22,10 @@ page_fault_isr:
     push %r13
     push %r14
     push %r15
-    /* stack has to be aligned */
-    mov %rsp, %rbp
-    and $-16, %rsp
-    call page_fault_handler
-    mov %rbp, %rsp
-    /* TODO: test for error code here and panic() */
-    pop %r15
+.endm
+
+.macro ISR_RESTORE_REGISTERS
+    // restore all the registers
     pop %r14
     pop %r13
     pop %r12
@@ -47,8 +40,44 @@ page_fault_isr:
     pop %rdx
     pop %rsi
     pop %rdi
+.endm
+
+.macro ISR_CALL func
+    // align the stack for the call to the handler function
+    mov %rsp, %rbp
+    and $-16, %rsp
+    call \func
+    // restore stack pointer, possibly unaligned
+    mov %rbp, %rsp
+.endm
+
+.hidden page_fault_isr
+.global page_fault_isr
+.type page_fault_isr, @function
+page_fault_isr:
+    ISR_STORE_REGISTERS
+    /* collect parameters for page fault handler */
+    mov 48(%rsp), %rdi /* error code is first parameter */
+    mov %cr2, %rsi /* PFLA is next parameter */
+    /* stack has to be aligned */
+    ISR_CALL page_fault_handler
+    /* TODO: test for error code here and panic() */
+    ISR_RESTORE_REGISTERS
     /* unwind the error code from the stack */
     add $8, %rsp
     /* leave the isr */
     iretq
 .size page_fault_isr, . - page_fault_isr
+
+.hidden general_protection_isr
+.global general_protection_isr
+.type general_protection_isr, @function
+general_protection_isr:
+    ISR_STORE_REGISTERS
+    // TODO: parameters?
+    ISR_CALL general_protection_handler
+    add $8, %rsp
+    ISR_RESTORE_REGISTERS
+    iretq
+.size general_protection_isr, . - general_protection_isr
+
diff --git a/kc/entry_x86_64.S b/kc/entry_x86_64.S
index 231953a..abea8ac 100644
--- a/kc/entry_x86_64.S
+++ b/kc/entry_x86_64.S
@@ -4,6 +4,7 @@
 .extern _DYNAMIC
 .extern kc_image_base
 
+.hidden kc_entry
 .global kc_entry
 .type kc_entry, @function
 kc_entry: