lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/mlibc/options/rtdl/aarch64/runtime.S b/lib/mlibc/options/rtdl/aarch64/runtime.S
new file mode 100644
index 0000000..c3e2cff
--- /dev/null
+++ b/lib/mlibc/options/rtdl/aarch64/runtime.S
@@ -0,0 +1,62 @@
+
+.global __mlibcTlsdescStatic
+.hidden __mlibcTlsdescStatic
+.type __mlibcTlsdescStatic,@function
+__mlibcTlsdescStatic:
+	ldr x0, [x0, #8]
+	ret
+
+// This function depends on the Tcb layout, since it pulls out the dtv pointer
+// out of the thread control block
+.global __mlibcTlsdescDynamic
+.hidden __mlibcTlsdescDynamic
+.type __mlibcTlsdescDynamic,@function
+__mlibcTlsdescDynamic:
+	stp x1, x2, [sp, #-16]!
+	ldr x0, [x0, #8]
+	ldp x1, x2, [x0] // tlsIndex, addend
+	mrs x0, tpidr_el0 // tp
+	ldr x0, [x0, #-104] // tp->dtvPointers
+	ldr x0, [x0, x1, lsl 3] // [tlsIndex]
+	add x0, x0, x2 // + addend
+	mrs x1, tpidr_el0 // tp
+	sub x0, x0, x1 // result - tp
+	ldp x1, x2, [sp], #16
+	ret
+
+.global pltRelocateStub
+pltRelocateStub:
+	// we need to save / restore all registers than can hold function arguments
+	// we do not need to save callee-saved registers as they will not be trashed by lazyRelocate
+	// TODO: save floating point argument registers
+
+	stp x0, x1, [sp, #-16]!
+
+	// pointer to PLT entry
+	ldr x1, [sp, #24]
+	ldr x0, [x16]
+	sub x1, x1, x0
+	asr x0, x0, #3
+
+	// pointer GOT
+	sub x0, x16, #8 // &PLTGOT[1]
+
+	stp x2, x3, [sp, #-16]!
+	stp x4, x5, [sp, #-16]!
+	stp x6, x7, [sp, #-16]!
+	stp x8, x30, [sp, #-16]!
+
+	bl lazyRelocate
+	mov x9, x0
+
+	ldp x8, x30, [sp], #16
+	ldp x6, x7, [sp], #16
+	ldp x4, x5, [sp], #16
+	ldp x2, x1, [sp], #16
+
+	ldp x0, x1, [sp], #16
+	add sp, sp, #16
+	br x9
+
+.section .note.GNU-stack,"",%progbits
+