From 0a1e9969a2739035737caebced7df571728ef621 Mon Sep 17 00:00:00 2001
From: Sergiusz Bazanski <q3k@q3k.org>
Date: Sun, 28 Jul 2019 16:35:29 +0200
Subject: [PATCH] l0dables: after review
---
l0dables/blinky/meson.build | 2 +-
l0dables/lib/crt.s | 51 +++++++++++++++++++------------------
l0dables/lib/hardware.c | 30 ++++++++++++++++------
l0dables/lib/meson.build | 2 +-
4 files changed, 50 insertions(+), 35 deletions(-)
diff --git a/l0dables/blinky/meson.build b/l0dables/blinky/meson.build
index 9a2fdb4c..9a5c199d 100644
--- a/l0dables/blinky/meson.build
+++ b/l0dables/blinky/meson.build
@@ -4,7 +4,7 @@ elf = executable(
name + '.elf',
'main.c',
build_by_default: true,
- dependencies: [l0dable_startup, api_caller, periphdriver],
+ dependencies: [l0dable_startup, api_caller],
link_whole: [l0dable_startup_lib],
link_args: [
'-Wl,-Map=' + meson.current_build_dir() + '/' + name + '.map',
diff --git a/l0dables/lib/crt.s b/l0dables/lib/crt.s
index be63692f..b811c4e6 100644
--- a/l0dables/lib/crt.s
+++ b/l0dables/lib/crt.s
@@ -4,9 +4,10 @@
* Also known as a startup file.
*
* We provide the following to l0dables:
- * - a 8k stack.
* - calling GCC initializers.
* - an ISR vector.
+ *
+ * The stack is provided by l0der.
*/
.syntax unified
@@ -39,11 +40,11 @@ __isr_vector:
.long 0 /* Reserved */
.long PendSV_Handler /* PendSV Handler */
.long SysTick_Handler /* SysTick Handler */
-
+
/* Device-specific Interrupts */
.long PF_IRQHandler /* 0x10 0x0040 16: Power Fail */
.long WDT0_IRQHandler /* 0x11 0x0044 17: Watchdog 0 */
- .long USB_IRQHandler /* 0x12 0x0048 18: USB */
+ .long DefaultHandler /* 0x12 0x0048 18: USB, used by core0, unoverridable */
.long RTC_IRQHandler /* 0x13 0x004C 19: RTC */
.long TRNG_IRQHandler /* 0x14 0x0050 20: True Random Number Generator */
.long TMR0_IRQHandler /* 0x15 0x0054 21: Timer 0 */
@@ -55,7 +56,7 @@ __isr_vector:
.long RSV11_IRQHandler /* 0x1B 0x006C 27: Reserved */
.long RSV12_IRQHandler /* 0x1C 0x0070 28: Reserved */
.long I2C0_IRQHandler /* 0x1D 0x0074 29: I2C0 */
- .long UART0_IRQHandler /* 0x1E 0x0078 30: UART 0 */
+ .long DefaultHandler /* 0x1E 0x0078 30: UART 0, used by core0, unoverridable */
.long UART1_IRQHandler /* 0x1F 0x007C 31: UART 1 */
.long SPI1_IRQHandler /* 0x20 0x0080 32: SPI1 */
.long SPI2_IRQHandler /* 0x21 0x0084 33: SPI2 */
@@ -65,8 +66,8 @@ __isr_vector:
.long RSV21_IRQHandler /* 0x25 0x0094 37: Reserved */
.long RSV22_IRQHandler /* 0x26 0x0098 38: Reserved */
.long FLC0_IRQHandler /* 0x27 0x009C 39: Flash Controller */
- .long GPIO0_IRQHandler /* 0x28 0x00A0 40: GPIO0 */
- .long GPIO1_IRQHandler /* 0x29 0x00A4 41: GPIO2 */
+ .long DefaultHandler /* 0x28 0x00A0 40: GPIO0, used by core0, unoverridable */
+ .long DefaultHandler /* 0x29 0x00A4 41: GPIO2, used by core0, unoverridable */
.long RSV26_IRQHandler /* 0x2A 0x00A8 42: GPIO3 */
.long TPU_IRQHandler /* 0x2B 0x00AC 43: Crypto */
.long DMA0_IRQHandler /* 0x2C 0x00B0 44: DMA0 */
@@ -133,7 +134,7 @@ __isr_vector:
.long RSV89_IRQHandler /* 0x69 0x01A4 105: UART 4 */
.long RSV90_IRQHandler /* 0x6A 0x01A8 106: UART 5 */
.long RSV91_IRQHandler /* 0x6B 0x01AC 107: Camera IF */
- .long RSV92_IRQHandler /* 0x6C 0x01B0 108: I3C */
+ .long RSV92_IRQHandler /* 0x6C 0x01B0 108: I3C */
.long HTMR0_IRQHandler /* 0x6D 0x01B4 109: HTmr */
.long HTMR1_IRQHandler /* 0x6E 0x01B8 109: HTmr */
@@ -157,27 +158,33 @@ Reset_Handler:
blx r0
/*
- * Spin forever.
+ * C code done, spin forever.
* TODO(q3k): let epicardium know we're done.
*/
.spin:
bl .spin
+ /*
+ * Used by __libc_init_array.
+ */
.globl _init
_init:
bx lr
- /* Macro to define default handlers. Default handler
- * will be weak symbol and just dead loops. They can be
- * overwritten by other handlers. */
- .macro def_irq_handler handler_name
- .align 1
+ /*
+ * The default handler for all IRQs just spins forwever.
+ * TODO(q3k): let epicardium know we've reached an infinite loop due to
+ * an exception and/or unhandled IRQ, perhaps by splitting
+ * DefaultHandler into multiple handlers that report different
+ * error conditions to epicardium (eg. unhandled IRQ, fault, ...)
+ */
.thumb_func
- .weak \handler_name
- .type \handler_name, %function
-\handler_name :
- b .
- .size \handler_name, . - \handler_name
+ .type DefaultHandler, %function
+DefaultHandler:
+ b .
+
+ .macro def_irq_handler handler_name
+ .weakref \handler_name, DefaultHandler
.endm
/*
@@ -191,11 +198,9 @@ _init:
def_irq_handler SVC_Handler
def_irq_handler DebugMon_Handler
def_irq_handler PendSV_Handler
- def_irq_handler Default_Handler
def_irq_handler PF_IRQHandler
def_irq_handler WDT0_IRQHandler
- def_irq_handler USB_IRQHandler
def_irq_handler RTC_IRQHandler
def_irq_handler TRNG_IRQHandler
def_irq_handler TMR0_IRQHandler
@@ -203,11 +208,9 @@ _init:
def_irq_handler TMR2_IRQHandler
def_irq_handler TMR3_IRQHandler
def_irq_handler TMR4_IRQHandler
- def_irq_handler TMR5_IRQHandler
def_irq_handler RSV11_IRQHandler
def_irq_handler RSV12_IRQHandler
def_irq_handler I2C0_IRQHandler
- def_irq_handler UART0_IRQHandler
def_irq_handler UART1_IRQHandler
def_irq_handler SPI1_IRQHandler
def_irq_handler SPI2_IRQHandler
@@ -217,8 +220,6 @@ _init:
def_irq_handler RSV21_IRQHandler
def_irq_handler RSV22_IRQHandler
def_irq_handler FLC0_IRQHandler
- def_irq_handler GPIO0_IRQHandler
- def_irq_handler GPIO1_IRQHandler
def_irq_handler RSV26_IRQHandler
def_irq_handler TPU_IRQHandler
def_irq_handler DMA0_IRQHandler
@@ -291,4 +292,4 @@ _init:
.section .cinterp
.asciz "card10-l0dable"
- .byte
+ .byte
diff --git a/l0dables/lib/hardware.c b/l0dables/lib/hardware.c
index e9325a1c..33233843 100644
--- a/l0dables/lib/hardware.c
+++ b/l0dables/lib/hardware.c
@@ -18,7 +18,7 @@
#include "icc_regs.h"
#include "pwrseq_regs.h"
-uint32_t SystemCoreClock = HIRC_FREQ >> 1;
+uint32_t SystemCoreClock = HIRC_FREQ >> 1;
void SystemCoreClockUpdate(void)
{
@@ -79,10 +79,8 @@ __weak void SystemInit() {
// newlib syscall to allow printf to work.
long _write(int fd, const char *buf, size_t cnt)
{
- /*
- * Only print one line at a time. Insert `\r` between lines so
- * they are properly displayed on the serial console.
- */
+ // Only print one line at a time. Insert `\r` between lines so
+ // they are properly displayed on the serial console.
size_t i, last = 0;
for (i = 0; i < cnt; i++) {
if (buf[i] == '\n') {
@@ -91,9 +89,7 @@ long _write(int fd, const char *buf, size_t cnt)
last = i;
}
}
- if (last != i) {
- epic_uart_write_str(&buf[last], cnt - last);
- }
+ epic_uart_write_str(&buf[last], cnt - last);
return cnt;
}
@@ -106,6 +102,24 @@ uint32_t _sbrk(int incr)
brk = (char *)&__heap_start;
}
+ // Ensure we don't overflow the heap by checking agsinst the current stack
+ // pointer (the heap grows towards the stack, and vice-versa).
+ //
+ // This is only a last-ditch attempt at saving ourselves from memory
+ // corruption. It doesn't prevent the stack from growing into the heap
+ // first.
+
+ void *sp;
+ __asm__ __volatile__ ("mov %0, sp" : "=r"(sp));
+
+ // Require a 'safe margin' of 4k between the heap and stack.
+ uint32_t stack_bottom = (uint32_t)sp - 4096;
+
+ if (((uint32_t)brk + incr) > stack_bottom) {
+ errno = ENOMEM;
+ return (uint32_t)-1;
+ }
+
char *prev_brk = brk;
brk += incr;
return (uint32_t)prev_brk;
diff --git a/l0dables/lib/meson.build b/l0dables/lib/meson.build
index 60d557d4..f2f16295 100644
--- a/l0dables/lib/meson.build
+++ b/l0dables/lib/meson.build
@@ -2,7 +2,7 @@ l0dable_startup_lib = static_library(
'l0dable-startup',
'crt.s',
'hardware.c',
- dependencies: [periphdriver, api_caller],
+ dependencies: [api_caller],
pic: true,
)
--
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