From fc6614dbd852533a73d92715d645b35fa9c981ea Mon Sep 17 00:00:00 2001
From: bzt <zoltan.baldaszti@gmail.com>
Date: Sat, 20 Jan 2018 14:55:42 +0100
Subject: [PATCH] Added EL3 handling code (untested)

---
 0F_executionlevel/OLVASSEL.md |   2 ++
 0F_executionlevel/README.md   |   2 ++
 0F_executionlevel/kernel8.img | Bin 960 -> 1000 bytes
 0F_executionlevel/main.c      |   2 +-
 0F_executionlevel/start.S     |  17 ++++++++++++++++-
 10_virtualmemory/kernel8.img  | Bin 4152 -> 4152 bytes
 10_virtualmemory/start.S      |  17 ++++++++++++++++-
 11_exceptions/kernel8.img     | Bin 8248 -> 8248 bytes
 11_exceptions/start.S         |  17 ++++++++++++++++-
 9 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/0F_executionlevel/OLVASSEL.md b/0F_executionlevel/OLVASSEL.md
index 7c52162e..d0bbf1cc 100644
--- a/0F_executionlevel/OLVASSEL.md
+++ b/0F_executionlevel/OLVASSEL.md
@@ -13,6 +13,8 @@ Exception return from AArch64 EL2 to AArch64 EL1 PC 0x8004c
 Current EL is: 00000001
 ```
 
+FIGYELEM: a teljesség kedvéért hozzáadtam az EL3-at is az Issue #6 miatt, bár semmilyen módon nem tudtam kipróbálni.
+
 Start
 -----
 
diff --git a/0F_executionlevel/README.md b/0F_executionlevel/README.md
index 076bef23..48a1fbf8 100644
--- a/0F_executionlevel/README.md
+++ b/0F_executionlevel/README.md
@@ -12,6 +12,8 @@ Exception return from AArch64 EL2 to AArch64 EL1 PC 0x8004c
 Current EL is: 00000001
 ```
 
+NOTE: For completeness, I've added code for EL3 too because of Issue #6, although I had no means to test it.
+
 Start
 -----
 
diff --git a/0F_executionlevel/kernel8.img b/0F_executionlevel/kernel8.img
index 95168bc2744d10fe1ed464a8cc8eaf384231ee7a..6f6943893d09d4d930814c2398b6d4c3b4f42920 100755
GIT binary patch
delta 159
zcmX@W{(^mih(RI?Lxh8q#Z?BDx=Hc|3?CU88A6n{HC$p6l)I`_38Wq5t|l=s2q*#R
z2h8)YO_T``z4!mWxDW#jaDW*fCN|12KG`@=n@N8G-^8>3|4)CwEUd-A<8=8EkPTEa
tf#Ct)#N$Br4iI04L1+z-{tGl|@((6W#wU}NnB9S77PA@Shsg_><pKKOJWT)q

delta 125
zcmaFCet>;~2!|pwLxh8q#np)}0irMd{}&fxfB_CL<G{p~GK?2C9@A#hXW*N7_W%Fs
z33W`tkAXB$dIEz3-^3F@_D&FAhCyg8kp2ra1*CPd0<$LLg~?vb?m%)9vl;UNW{$}h
LnZ+kRU}ggVpkOVJ

diff --git a/0F_executionlevel/main.c b/0F_executionlevel/main.c
index 2e2bad07..935c0694 100644
--- a/0F_executionlevel/main.c
+++ b/0F_executionlevel/main.c
@@ -36,7 +36,7 @@ void main()
     asm volatile ("mrs %0, CurrentEL" : "=r" (el));
 
     uart_puts("Current EL is: ");
-    uart_hex(el>>2);
+    uart_hex((el>>2)&3);
     uart_puts("\n");
 
     // echo everything back
diff --git a/0F_executionlevel/start.S b/0F_executionlevel/start.S
index 34cf99c8..33b5f4f9 100644
--- a/0F_executionlevel/start.S
+++ b/0F_executionlevel/start.S
@@ -42,7 +42,22 @@ _start:
 
     // set up EL1
     mrs     x0, CurrentEL
-    cmp     x0, #4
+    and     x0, x0, #12 // clear reserved bits
+
+    // running at EL3?
+    cmp     x0, #12
+    bne     5f
+    // should never be executed, just for completeness
+    mov     x2, #0x5b1
+    msr     scr_el3, x2
+    mov     x2, #0x3c9
+    msr     spsr_el3, x2
+    adr     x2, 5f
+    msr     elr_el3, x2
+    eret
+
+    // running at EL2?
+5:  cmp     x0, #4
     beq     5f
     msr     sp_el1, x1
     // enable CNTP for EL1
diff --git a/10_virtualmemory/kernel8.img b/10_virtualmemory/kernel8.img
index c5438321ba3d22ee265d3185065a000c9c14238c..ba67353120b5d47249e4f778420e063e67d80c15 100755
GIT binary patch
delta 98
zcmdm?utQ;jh=C$2Lxh8q#Z?BDx=Hc|3?CU88A6n{HC$p6l)I`_38Wq5t|l=s2q*#R
z2h8)YO_a%DyuPv1f{}5-=0l8&nFJHWC!YKNe>wvL!-PkF=1*c+u(^ySi+eJMfB^tZ
C(<21{

delta 62
zcmV-E0KxybAh;lq6bRu109ZgmIMtCvYysi1u{Z$%0JG`=qXH4Y7Lm^X|Cay&0FdJR
UpOOFovz`QM3zHBAD3b^fFz&4v8UO$Q

diff --git a/10_virtualmemory/start.S b/10_virtualmemory/start.S
index 142f2285..6e757440 100644
--- a/10_virtualmemory/start.S
+++ b/10_virtualmemory/start.S
@@ -42,7 +42,22 @@ _start:
 
     // set up EL1
     mrs     x0, CurrentEL
-    cmp     x0, #4
+    and     x0, x0, #12 // clear reserved bits
+
+    // running at EL3?
+    cmp     x0, #12
+    bne     5f
+    // should never be executed, just for completeness
+    mov     x2, #0x5b1
+    msr     scr_el3, x2
+    mov     x2, #0x3c9
+    msr     spsr_el3, x2
+    adr     x2, 5f
+    msr     elr_el3, x2
+    eret
+
+    // running at EL2?
+5:  cmp     x0, #4
     beq     5f
     msr     sp_el1, x1
     // enable CNTP for EL1
diff --git a/11_exceptions/kernel8.img b/11_exceptions/kernel8.img
index 4357c4bdeaf56525dd3d53f1e0b1cde33ae34537..fcd9f4a27cde2f17a9d6127ebfcf166ea0e0ba20 100755
GIT binary patch
delta 94
zcmdntu)|@3j0OWs-6VMfhL4Pl3?WL}8ZI#j%3W2e1kw(2SCbeR1eAdE1LpbHCdyba
xC3#K^lapQO!4PrCok60Bfx*PSh2e)23q#<d|Nl*OnHi>B-8j*meG`X;1OTn;9|iyb

delta 59
zcmV-B0L1^eK)67V9Fasg0-{QhejXs<NdQ;^NdOpv001;UgaG(L1OQQ@|Nk{N0|1oY
R|Nj@Uz(5C)&@8eDI2doG6}SKZ

diff --git a/11_exceptions/start.S b/11_exceptions/start.S
index aa21910b..f940f0c8 100644
--- a/11_exceptions/start.S
+++ b/11_exceptions/start.S
@@ -42,7 +42,22 @@ _start:
 
     // set up EL1
     mrs     x0, CurrentEL
-    cmp     x0, #4
+    and     x0, x0, #12 // clear reserved bits
+
+    // running at EL3?
+    cmp     x0, #12
+    bne     5f
+    // should never be executed, just for completeness
+    mov     x2, #0x5b1
+    msr     scr_el3, x2
+    mov     x2, #0x3c9
+    msr     spsr_el3, x2
+    adr     x2, 5f
+    msr     elr_el3, x2
+    eret
+
+    // running at EL2?
+5:  cmp     x0, #4
     beq     5f
     msr     sp_el1, x1
     // enable CNTP for EL1