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 --- arch/arm/cpu/u-boot.lds | 32 +++++++++++++++++++++++--------- arch/arm/include/asm/armv7.h | 2 ++ arch/arm/include/asm/psci.h | 4 ++++ arch/arm/lib/sections.c | 2 ++ 4 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds index ba177787d23c..002706ae635d 100644 --- a/arch/arm/cpu/u-boot.lds +++ b/arch/arm/cpu/u-boot.lds @@ -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 */ } diff --git a/arch/arm/include/asm/armv7.h b/arch/arm/include/asm/armv7.h index 423fc7011166..a20702e612b1 100644 --- a/arch/arm/include/asm/armv7.h +++ b/arch/arm/include/asm/armv7.h @@ -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 */
diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h index bc5edda73f00..dab576997654 100644 --- a/arch/arm/include/asm/psci.h +++ b/arch/arm/include/asm/psci.h @@ -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>
diff --git a/arch/arm/lib/sections.c b/arch/arm/lib/sections.c index 6a9452241834..952e8ae49bf4 100644 --- a/arch/arm/lib/sections.c +++ b/arch/arm/lib/sections.c @@ -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")));