[PATCH v2 3/3] ARM: rpi: use ENTRY_FUNCTION_WITHSTACK to prepare for ARM64 support
Ahmad Fatoum
a.fatoum at pengutronix.de
Fri Jan 14 00:42:27 PST 2022
arm_setup_stack used in start_raspberry_pi is not safe on ARM64, due to
lack of __naked support. since 76bced6fe146 ("ARM: document
arm_setup_stack() pitfalls"), its use in ARM64 code is a compile-time
error.
The Raspberry Pi 4 support will be ARM64. To allow it to reuse
the existing low-level code, use the new ENTRY_FUNCTION_WITHSTACK,
which will set up stack appropriately for both ARM32 and ARM64.
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
arch/arm/boards/raspberry-pi/lowlevel.c | 35 ++++++++++++-------------
1 file changed, 17 insertions(+), 18 deletions(-)
diff --git a/arch/arm/boards/raspberry-pi/lowlevel.c b/arch/arm/boards/raspberry-pi/lowlevel.c
index 29162ff02d54..e9314fb27b25 100644
--- a/arch/arm/boards/raspberry-pi/lowlevel.c
+++ b/arch/arm/boards/raspberry-pi/lowlevel.c
@@ -33,52 +33,51 @@ static void copy_vc_fdt(void *dest, void *src, unsigned long max_size)
memmove(dest, src, size);
}
+/* A pointer to the FDT created by VideoCore was passed to us in r2. We
+ * reserve some memory just above the region used for Barebox and copy
+ * this FDT there. We fetch it from there later in rpi_devices_init().
+ */
+#define rpi_stack_top(memsize) \
+ arm_mem_stack_top(BCM2835_SDRAM_BASE, BCM2835_SDRAM_BASE + memsize - VIDEOCORE_FDT_SZ)
+
/* Must be inline since stack isn't setup yet. */
static inline void start_raspberry_pi(unsigned long memsize, void *fdt,
void *vc_fdt)
{
- void *saved_vc_fdt;
- unsigned long membase = BCM2835_SDRAM_BASE;
-
- /* A pointer to the FDT created by VideoCore was passed to us in r2. We
- * reserve some memory just above the region used for Basebox and copy
- * this FDT there. We fetch it from there later in rpi_devices_init().*/
- memsize -= VIDEOCORE_FDT_SZ;
+ unsigned long endmem = rpi_stack_top(memsize);
arm_cpu_lowlevel_init();
- /* Copied from barebox_arm_entry(). We need stack here early
- * for normal function calls to work. */
- arm_setup_stack(arm_mem_stack_top(membase, membase + memsize));
+ copy_vc_fdt((void *)endmem, vc_fdt, VIDEOCORE_FDT_SZ);
fdt += get_runtime_offset();
- saved_vc_fdt = (void *)(membase + memsize);
- copy_vc_fdt(saved_vc_fdt, vc_fdt, VIDEOCORE_FDT_SZ);
-
- barebox_arm_entry(membase, memsize, fdt);
+ barebox_arm_entry(BCM2835_SDRAM_BASE, endmem - BCM2835_SDRAM_BASE, fdt);
}
+#define RPI_ENTRY_FUNCTION(name, memsize, r2) \
+ ENTRY_FUNCTION_WITHSTACK(name, rpi_stack_top(memsize), __r0, __r1, r2)
+
extern char __dtb_bcm2835_rpi_start[];
-ENTRY_FUNCTION(start_raspberry_pi1, r0, r1, r2)
+RPI_ENTRY_FUNCTION(start_raspberry_pi1, SZ_128M, r2)
{
start_raspberry_pi(SZ_128M, __dtb_bcm2835_rpi_start, (void *)r2);
}
extern char __dtb_bcm2836_rpi_2_start[];
-ENTRY_FUNCTION(start_raspberry_pi2, r0, r1, r2)
+RPI_ENTRY_FUNCTION(start_raspberry_pi2, SZ_512M, r2)
{
start_raspberry_pi(SZ_512M, __dtb_bcm2836_rpi_2_start, (void *)r2);
}
extern char __dtb_bcm2837_rpi_3_start[];
-ENTRY_FUNCTION(start_raspberry_pi3, r0, r1, r2)
+RPI_ENTRY_FUNCTION(start_raspberry_pi3, SZ_512M, r2)
{
start_raspberry_pi(SZ_512M, __dtb_bcm2837_rpi_3_start, (void *)r2);
}
extern char __dtb_bcm2837_rpi_cm3_start[];
-ENTRY_FUNCTION(start_raspberry_pi_cm3, r0, r1, r2)
+RPI_ENTRY_FUNCTION(start_raspberry_pi_cm3, SZ_512M, r2)
{
start_raspberry_pi(SZ_512M, __dtb_bcm2837_rpi_cm3_start, (void *)r2);
}
--
2.30.2
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