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ARM: Add an empty secure stack section 

Until now we've been using memory beyond psci_text_end as stack space
for the secure monitor or PSCI implementation, even if space was not
allocated for it.

This was partially fixed in ("ARM: allocate extra space for PSCI stack
in secure section during link phase"). However, calculating stack space
from psci_text_end in one place, while allocating the space in another
is error prone.

This patch adds a separate empty secure stack section, with space for
CONFIG_ARMV7_PSCI_NR_CPUS stacks, each 1 KB. There's also
__secure_stack_start and __secure_stack_end symbols. The linker script
handles calculating the correct VMAs for the stack section. For
platforms that relocate/copy the secure monitor before using it, the
space is not allocated in the executable, saving space.

For platforms that do not define CONFIG_ARMV7_PSCI_NR_CPUS, a whole page
of stack space for 4 CPUs is allocated, matching the previous behavior.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Chen-Yu Tsai 2016-06-19 12:38:36 +08:00 committed by Hans de Goede
parent dbf38aabd9
commit 980d6a5511
4 changed files with 31 additions and 9 deletions
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32
arch/arm/cpu/u-boot.lds
View File

@ -8,6 +8,7 @@
*/
#include <config.h>
#include <asm/psci.h>
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
OUTPUT_ARCH(arm)
@ -68,18 +69,31 @@ SECTIONS
*(._secure.text)
}
. = LOADADDR(.__secure_start) +
SIZEOF(.__secure_start) +
SIZEOF(.secure_text);
.secure_stack ALIGN(ADDR(.secure_text) + SIZEOF(.secure_text),
CONSTANT(COMMONPAGESIZE)) (NOLOAD) :
#ifdef __ARMV7_PSCI_STACK_IN_RAM
/* Align to page boundary and skip 2 pages */
. = (. & ~ 0xfff) + 0x2000;
#undef __ARMV7_PSCI_STACK_IN_RAM
AT(ADDR(.secure_stack))
#else
AT(LOADADDR(.secure_text) + SIZEOF(.secure_text))
#endif
{
KEEP(*(.__secure_stack_start))
/* Skip addreses for stack */
. = . + CONFIG_ARMV7_PSCI_NR_CPUS * ARM_PSCI_STACK_SIZE;
/* Align end of stack section to page boundary */
. = ALIGN(CONSTANT(COMMONPAGESIZE));
KEEP(*(.__secure_stack_end))
}
#ifndef __ARMV7_PSCI_STACK_IN_RAM
/* Reset VMA but don't allocate space if we have secure SRAM */
. = LOADADDR(.secure_stack);
#endif
__secure_end_lma = .;
.__secure_end : AT(__secure_end_lma) {
.__secure_end : AT(ADDR(.__secure_end)) {
*(.__secure_end)
LONG(0x1d1071c); /* Must output something to reset LMA */
}

2
arch/arm/include/asm/armv7.h
View File

@ -126,6 +126,8 @@ void _smp_pen(void);
extern char __secure_start[];
extern char __secure_end[];
extern char __secure_stack_start[];
extern char __secure_stack_end[];
#endif /* CONFIG_ARMV7_NONSEC */

4
arch/arm/include/asm/psci.h
View File

@ -47,6 +47,10 @@
#define ARM_PSCI_0_2_FN_SYSTEM_OFF ARM_PSCI_0_2_FN(8)
#define ARM_PSCI_0_2_FN_SYSTEM_RESET ARM_PSCI_0_2_FN(9)
/* 1KB stack per core */
#define ARM_PSCI_STACK_SHIFT 10
#define ARM_PSCI_STACK_SIZE (1 << ARM_PSCI_STACK_SHIFT)
#ifndef __ASSEMBLY__
#include <asm/types.h>

2
arch/arm/lib/sections.c
View File

@ -27,6 +27,8 @@ char __rel_dyn_start[0] __attribute__((section(".__rel_dyn_start")));
char __rel_dyn_end[0] __attribute__((section(".__rel_dyn_end")));
char __secure_start[0] __attribute__((section(".__secure_start")));
char __secure_end[0] __attribute__((section(".__secure_end")));
char __secure_stack_start[0] __attribute__((section(".__secure_stack_start")));
char __secure_stack_end[0] __attribute__((section(".__secure_stack_end")));
char __efi_runtime_start[0] __attribute__((section(".__efi_runtime_start")));
char __efi_runtime_stop[0] __attribute__((section(".__efi_runtime_stop")));
char __efi_runtime_rel_start[0] __attribute__((section(".__efi_runtime_rel_start")));