Saved all registers required by the system V ABI. (Except for the disabled SSE2 one.)

diff --git a/kernel/src/ring3.S b/kernel/src/ring3.S
index 6d9b55fa59bde24bd5776dde7148d6576f2b3ed3..a3a0e7698a21ff9bb42d736556e57905026f1993 100644 (file)
--- a/kernel/src/ring3.S
+++ b/kernel/src/ring3.S
@@ -37,17 +37,50 @@ load_tss:
 
 .globl syscall_64bit_handler
 syscall_64bit_handler:
-       push %rcx
+       push %rax
+       movq current_pid, %rax
+       shl $17, %rax # * 0x1000 * 32 (i.e. the size of a process)
+       addq process_struct_table, %rax
+       # %rax now contains the address of the current process struct.
+       movq %rcx, 0x10(%rax) # %rip
+       movq %rbx, 0x18(%rax)
+       movq %rsp, 0x20(%rax) # original %rsp
+       addq $8, 0x20(%rax) # here as well
+       movq %rbp, 0x28(%rax)
+       movq %r12, 0x30(%rax)
+       movq %r13, 0x38(%rax)
+       movq %r14, 0x40(%rax)
+       movq %r15, 0x48(%rax)
+       fstcw 0x58(%rax)
+       # Current process registers have now all been updated.
+       pop %rax
+
        mov %r10, %rcx
        cmp $syscall_n, %rax
        jae incorrect_syscall
        callq *syscalls_call_table(, %rax, 8)
-       pop %rcx
+syscall_end:
+       movq %rax, %rbp
+       movq current_pid, %rax
+       shl $17, %rax # * 0x1000 * 32 (i.e. the size of a process)
+       addq process_struct_table, %rax
+       # %rax now contains the address of the current process struct.
+       movq 0x10(%rax), %rcx # %rip
+       movq 0x18(%rax), %rbx
+       movq 0x20(%rax), %rsp
+       push %rbp # %rax
+       movq 0x28(%rax), %rbp
+       movq 0x30(%rax), %r12
+       movq 0x38(%rax), %r13
+       movq 0x40(%rax), %r14
+       movq 0x48(%rax), %r15
+       fldcw 0x58(%rax)
+       # Current process registers have now all been updated.
+       pop %rax
        sysretq
 incorrect_syscall:
        call syscall_rax_error_handler
-       pop %rcx
-       sysretq
+       jmp syscall_end
 
 .section .rodata
 syscalls_call_table:
@@ -55,3 +88,4 @@ syscalls_call_table:
        .quad syscall_println
        .quad syscall_print_low_mmap
 .set syscall_n, 3
+process_struct_table: .quad 0xFFFFC00000000000

diff --git a/kernel/src/ring3.hpp b/kernel/src/ring3.hpp
index 1450d04278bc00bc3af2860b5e09be37a06aba19..7d26636eb441d2ad7c9da03830ea4c8b864a111a 100644 (file)
--- a/kernel/src/ring3.hpp
+++ b/kernel/src/ring3.hpp
@@ -71,7 +71,7 @@ struct process {
        std::uint64_t r13;
        std::uint64_t r14;
        std::uint64_t r15;
-       std::uint64_t mxcsr;
+       std::uint64_t mxcsr; // UNUSED for now.
        std::uint64_t x87cw;
        port ports[4093];
 };
@@ -88,6 +88,6 @@ inline bool port_exists(std::uint64_t pid, std::uint64_t port) {
        return port < 4093 && process_exists(pid) && get_process(pid).ports[port].exists;
 }
 
-extern std::uint64_t current_pid;
+extern "C" std::uint64_t current_pid;
 
 } // namespace os