cortexm_common/Makefile.include: set RIOTBOOT_HRD_LEN for cortex-m

- Since the Vector table must be naturally aligned to the next power
  of two of the amount of supported ISR, and the table will be
  placed after riotboot_hdr, we must ensure RIOTBOOT_HRD_LEN has the
  same alignment.
This commit is contained in:
francisco 2019-06-06 11:07:34 +02:00
parent d6b8df1ff7
commit 4acceefa65

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@ -25,6 +25,33 @@ LINKFLAGS += $(if $(ROM_OFFSET),$(LINKFLAGPREFIX)--defsym=_rom_offset=$(ROM_OFFS
# FW_ROM_LEN: rom length to use for firmware linking. Allows linking only in a section of the rom. # FW_ROM_LEN: rom length to use for firmware linking. Allows linking only in a section of the rom.
LINKFLAGS += $(if $(FW_ROM_LEN),$(LINKFLAGPREFIX)--defsym=_fw_rom_length=$(FW_ROM_LEN)) LINKFLAGS += $(if $(FW_ROM_LEN),$(LINKFLAGPREFIX)--defsym=_fw_rom_length=$(FW_ROM_LEN))
# Cortex-M0+/1/3/4/7 riotboot settings
# From ARMv7-M (M4, M3, M7) architecture reference manual, section B1.5.3
# https://static.docs.arm.com/ddi0403/e/DDI0403E_d_armv7m_arm.pdf
# "The Vector table must be naturally aligned to a power of two whose alignment
# value is greater than or equal to number of Exceptions supported x 4"
# From ARMv6-M (M0, M0+, M1) architecture reference manual, section B1.5.3
# https://static.docs.arm.com/ddi0419/d/DDI0419D_armv6m_arm.pdf
# "The table offset address that VTOR defines is 32-word aligned. Where more
# than 16 external interrupts are used, the offset word alignment must be
# increased to accommodate vectors for all the exceptions and interrupts
# supported and keep the required table size naturally aligned."
# For reference on the max number in interrupts per processor look in The
# technical reference manual "Interrupt Controller Type Register, ICTR" section.
# * For M4, M3 & M7: Maximum of 256 exceptions (256*4 bytes == 0x400).
# * For M0, M0+ & M1: Maximum of 48 exceptions (48*4 bytes = 192 bytes ~= 0x100).
# The values defined here are a theoretical maximum, in practice most cpu's
# CPU_IRQ_NUMOF value is around 100, in these cases the value can be reduced
# accordingly in the cpu Makefile.include, e.g: `kinetis/Makefile.include`
ifneq (,$(filter cortex-m2% cortex-m4% cortex-m3% cortex-m7%,$(CPU_ARCH)))
RIOTBOOT_HDR_LEN ?= 0x400
else
RIOTBOOT_HDR_LEN ?= 0x100
endif
# Configure riotboot bootloader and slot lengths # Configure riotboot bootloader and slot lengths
# 4KB are currently enough # 4KB are currently enough