Re: [bootwrapper PATCH v2 11/13] Announce locations of memory objects

Andre Przywara
2022-01-14T15:32:21Z

On Fri, 14 Jan 2022 10:56:51 +0000
Mark Rutland <mark.rutland@arm.com> wrote:

Hi Mark,

> To make it easier to debug boot failures, log the location of memory
> objects at boot time.
>
> This is logged to the serial console as:
>
> | Boot-wrapper v0.2
> | Entered at EL3
> | Memory layout:
> | [0000000080000000..0000000080001f90] => boot-wrapper
> | [000000008000fff8..0000000080010000] => mbox
> | [0000000080200000..00000000822af200] => kernel
> | [0000000088000000..0000000088002857] => dtb
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> ---
> common/init.c | 27 +++++++++++++++++++++++++++
> common/platform.c | 13 +++++++++++++
> include/platform.h | 2 ++
> model.lds.S | 20 ++++++++++++++------
> 4 files changed, 56 insertions(+), 6 deletions(-)
>
> diff --git a/common/init.c b/common/init.c
> index 2600f73..fc74b9e 100644
> --- a/common/init.c
> +++ b/common/init.c
> @@ -14,6 +14,32 @@ static void announce_bootwrapper(void)
> print_string("Boot-wrapper v0.2\r\n");
> }
>
> +#define announce_object(object, desc) \
> +do { \
> + extern char object##__start[]; \
> + extern char object##__end[]; \
> + print_string("["); \
> + print_ulong_hex((unsigned long)object##__start); \
> + print_string(".."); \
> + print_ulong_hex((unsigned long)object##__end); \
> + print_string("] => " desc "\r\n"); \
> +} while (0)
> +
> +static void announce_objects(void)
> +{
> + print_string("Memory layout:\r\n");
> + announce_object(text, "boot-wrapper");
> + announce_object(mbox, "mbox");
> + announce_object(kernel, "kernel");
> +#ifdef XEN
> + announce_object(xen, "xen");
> +#endif
> + announce_object(dtb, "dtb");
> +#ifdef USE_INITRD
> + announce_object(filesystem, "initrd");
> +#endif
> +}
> +
> void announce_arch(void);
>
> void cpu_init_bootwrapper(void)
> @@ -22,6 +48,7 @@ void cpu_init_bootwrapper(void)
> init_uart();
> announce_bootwrapper();
> announce_arch();
> + announce_objects();
> print_string("\r\n");
> init_platform();
> }
> diff --git a/common/platform.c b/common/platform.c
> index 80d0562..26e5944 100644
> --- a/common/platform.c
> +++ b/common/platform.c
> @@ -52,6 +52,19 @@ void print_string(const char *str)
> print_char(*str++);
> }
>
> +#define HEX_CHARS_PER_LONG (2 * sizeof(long))
> +
> +void print_ulong_hex(unsigned long val)
> +{
> + const char hex_chars[16] = "0123456789abcdef";

This breaks the build for me (I guess because of the const?):
-------------------
ld --gc-sections arch/aarch64/boot.o arch/aarch64/stack.o arch/aarch64/utils.o arch/aarch64/init.o arch/aarch64/psci.o common/boot.o common/bakery_lock.o common/platform.o common/lib.o common/init.o common/psci.o common/gic-v3.o -o linux-system.axf --script=model.lds
ld: common/platform.o: in function `print_ulong_hex':
/src/boot-wrapper-aarch64.git/common/platform.c:58: undefined reference to `__stack_chk_guard'
ld: /src/boot-wrapper-aarch64.git/common/platform.c:58: undefined reference to `__stack_chk_guard'
ld: /src/boot-wrapper-aarch64.git/common/platform.c:66: undefined reference to `__stack_chk_fail'
/src/boot-wrapper-aarch64.git/common/platform.c:66:(.text.print_ulong_hex+0xa0): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__stack_chk_fail'
make: *** [Makefile:684: linux-system.axf] Error 1
------------------

Adding -fno-stack-protector fixes it again.

I am still checking on each one of those compiler options, shall I send a
smaller version of that patch 3/9 of mine, meanwhile, just carrying the
uncontested -ffreestanding and -nostdlib, plus -fno-stack-protector?

Cheers,
Andre

> + int i;
> +
> + for (i = HEX_CHARS_PER_LONG - 1; i >= 0; i--) {
> + int v = (val >> (4 * i)) & 0xf;
> + print_char(hex_chars[v]);
> + }
> +}
> +
> void init_uart(void)
> {
> /*
> diff --git a/include/platform.h b/include/platform.h
> index 237b481..c88e124 100644
> --- a/include/platform.h
> +++ b/include/platform.h
> @@ -11,6 +11,8 @@
>
> void print_char(char c);
> void print_string(const char *str);
> +void print_ulong_hex(unsigned long val);
> +
> void init_uart(void);
>
> void init_platform(void);
> diff --git a/model.lds.S b/model.lds.S
> index d4e7e13..dacaa25 100644
> --- a/model.lds.S
> +++ b/model.lds.S
> @@ -35,46 +35,54 @@ SECTIONS
> * the boot section's *(.data)
> */
> .kernel (PHYS_OFFSET + KERNEL_OFFSET): {
> - kernel = .;
> + kernel__start = .;
> KERNEL
> + kernel__end = .;
> }
>
> #ifdef XEN
> .xen (PHYS_OFFSET + XEN_OFFSET): {
> - xen = .;
> + xen__start = .;
> XEN
> + xen__end = .;
> }
>
> - entrypoint = xen;
> + entrypoint = xen__start;
> #else
> - entrypoint = kernel;
> + entrypoint = kernel__start;
> #endif
>
> .dtb (PHYS_OFFSET + FDT_OFFSET): {
> + dtb__start = .;
> dtb = .;
> ./fdt.dtb
> + dtb__end = .;
> }
>
> #ifdef USE_INITRD
> .filesystem (PHYS_OFFSET + FS_OFFSET): {
> - filesystem = .;
> + filesystem__start = .;
> FILESYSTEM
> - fs_size = . - filesystem;
> + filesystem__end = .;
> }
> #endif
>
> .boot PHYS_OFFSET: {
> + text__start = .;
> *(.init)
> *(.text*)
> *(.data* .rodata* .bss* COMMON)
> *(.vectors)
> *(.stack)
> PROVIDE(etext = .);
> + text__end = .;
> }
>
> .mbox (PHYS_OFFSET + MBOX_OFFSET): {
> + mbox__start = .;
> mbox = .;
> QUAD(0x0)
> + mbox__end = .;
> }
>
> ASSERT(etext <= (PHYS_OFFSET + TEXT_LIMIT), ".text overflow!")