From a9c0fcdfde058e90fe361ca9da24b56fc6db1b50 Mon Sep 17 00:00:00 2001
From: Curle <curle@gemwire.uk>
Date: Mon, 9 Nov 2020 18:44:42 +0000
Subject: [PATCH] Adjust the crt0 file to insert a null stack frame before
 calling the kernel. Provides a solid base for the stack unwinding.

---
 global/crt0.c   |   2 ++
 global/crt0.o   | Bin 1360 -> 960 bytes
 global/crt0.old | Bin 0 -> 1360 bytes
 global/crt0.s   |  20 ++++++++++++++++----
 4 files changed, 18 insertions(+), 4 deletions(-)
 create mode 100644 global/crt0.old

diff --git a/global/crt0.c b/global/crt0.c
index 5f3ba44..777ec95 100644
--- a/global/crt0.c
+++ b/global/crt0.c
@@ -6,6 +6,8 @@ extern void _init();
 
 void _start() {
     _init();
+    unsigned long long zero = 0;
+    __asm__ __volatile__("movq %%rbp, %[input]" : : [input] "m" (zero) : );
     int ex = Main();
     Exit(ex);
 }
\ No newline at end of file
diff --git a/global/crt0.o b/global/crt0.o
index af9b40e1fa048808a004c3fbddf009ab9d5896bb..d3aa69a8d35c0092690a10b888f968b74be421ee 100644
GIT binary patch
literal 960
zcmb<-^>JfjWMqH=Mg}_u1P><4z;FOb&;cy$z`()4&JgO+`P8HNjev*YffpcQ55u=`
zX6JFR5Lh)nf*Grg3=GUbhz&3^uwV#-oF|0E91ftk0ETJ?20k3(!Z^ek;)_cXi%J;c
zGxIV_7<>~m^B7z!fGi%U*-Sv16^Q@*hX8RTaW*7zc_eXmByk44;>z5T#3UeHQUswh
zV639loJ75n)QS=Yy_Cd~L<YU2;$o;V6jKU76F^}Haw9TufO3?P1%Yg&WB`_t29luI
zZ~*fVgacHe2UG|YHXtETe1L!igkn$w(jam4m`;Yuqf_Yi>i`vi%p_Mo$UIQop@R&l
wzyT-?3LlU^(cRAp6hpTgq(uYjP?$eKVjzI-enFrZHvJt?g@#~V2m)O{0D56WrvLx|

literal 1360
zcmbu9Jxc>Y5QgUxKjT*v1yR8?ih>+kDHeJXVj`%8U>(kQY9NVl*&^B~2tu&Q&#@FN
z#D8HUSlHMHbl%*KS<g$OZ`hsLXLojIKQ339-R+oVk;tMAYPW<EHDYbwX}Jy!P=XF~
z_1E0Zd-5La4OQE#XPS4JX8oy!8_$oFO{dpW3)%g{#nh_3VlVUPafGm}%LB4%No#tr
zx39qo%rHZNmQZaCCvRivp`KG7fOZEV_b&SQjOva@?u;nTzbM6drYOa!Ckpc{-M=_;
z9W&N#?S<J0m*lU}L=zqOR0mE4UoG1O%2$=^E6NuuMMZmVu|k;|do--q!1W=Q=4YTu
zgZCSJ&fp1yrwnd91tPn8QC98|TjdA#Og!H!xwi6ZitJ-oxnv(zt7I3>%Vn>^tkvzE
z<xhOK?CI(MZICD4K=_6nW{{kJ&<e(i4?E2Tx9)H;^`bwDoQ60{AXrGwbDn+h@QW&8
zP=xff-#y3=bN)4cg<~-%zAaO-{+J2bm-WSNYWCxfnO$>%)&lcg%l-wdvlDfG3wlC1
zC&b~7Bwjf32(Qg3_*cProhaUHFWOuni3bm#9r_=1+$<V~WZ!~D*@=pGbW%GqP}^|)
E7hJnv&;S4c

diff --git a/global/crt0.old b/global/crt0.old
new file mode 100644
index 0000000000000000000000000000000000000000..af9b40e1fa048808a004c3fbddf009ab9d5896bb
GIT binary patch
literal 1360
zcmbu9Jxc>Y5QgUxKjT*v1yR8?ih>+kDHeJXVj`%8U>(kQY9NVl*&^B~2tu&Q&#@FN
z#D8HUSlHMHbl%*KS<g$OZ`hsLXLojIKQ339-R+oVk;tMAYPW<EHDYbwX}Jy!P=XF~
z_1E0Zd-5La4OQE#XPS4JX8oy!8_$oFO{dpW3)%g{#nh_3VlVUPafGm}%LB4%No#tr
zx39qo%rHZNmQZaCCvRivp`KG7fOZEV_b&SQjOva@?u;nTzbM6drYOa!Ckpc{-M=_;
z9W&N#?S<J0m*lU}L=zqOR0mE4UoG1O%2$=^E6NuuMMZmVu|k;|do--q!1W=Q=4YTu
zgZCSJ&fp1yrwnd91tPn8QC98|TjdA#Og!H!xwi6ZitJ-oxnv(zt7I3>%Vn>^tkvzE
z<xhOK?CI(MZICD4K=_6nW{{kJ&<e(i4?E2Tx9)H;^`bwDoQ60{AXrGwbDn+h@QW&8
zP=xff-#y3=bN)4cg<~-%zAaO-{+J2bm-WSNYWCxfnO$>%)&lcg%l-wdvlDfG3wlC1
zC&b~7Bwjf32(Qg3_*cProhaUHFWOuni3bm#9r_=1+$<V~WZ!~D*@=pGbW%GqP}^|)
E7hJnv&;S4c

literal 0
HcmV?d00001

diff --git a/global/crt0.s b/global/crt0.s
index d50d2cd..9b029e7 100644
--- a/global/crt0.s
+++ b/global/crt0.s
@@ -1,10 +1,22 @@
 .section .text
 .global _start
 .global _init
-.global main
-.global _fini
+.global Main
+.global Exit
 .type _start, @function
 _start:
+	push %rbp
+	movq %rsp, %rbp
+	sub $0x10, %rsp
+
+	xor %rax, %rax
 	call _init
-	call main
-	call _fini
\ No newline at end of file
+
+	xor %rbp, %rbp
+	
+	xor %rax, %rax
+	call Main
+
+	movq %rax, %rdi
+	call Exit
+	
\ No newline at end of file