Re: [PATCH v2 4/4] board_f.c: Insure 16 alignment of start_addr_sp and reserved memory

On 1/22/20 6:52 AM, Patrick Delaunay wrote:

Add a function reserve_sp() to reserved memory with 16 bits alignment after the stack pointer (gd->start_addr_sp) and use this new function in board_f.c to reserve all the memory area (malloc, board, gd, fdt, bootstage, stacks).

This 16 byte alignment is needed for cast on struct pointer for the reserved memory, for example:

• x86_64 ABI: https://reviews.llvm.org/D30049: 16 bytes
• ARMv8 Instruction Set Overview: quad word, 16 bytes

An other alignment value could be needed for other architecture.

diff --git a/common/board_f.c b/common/board_f.c

+/*

• • reserve after start_addr_sp the requested size and make the stack pointer
• • 16-byte aligned, this alignment is needed for cast on the reserved memory
• • ref = x86_64 ABI: https://reviews.llvm.org/D30049: 16 bytes

• • = ARMv8 Instruction Set Overview: quad word, 16 bytes
    

• */

+static unsigned long reserve_sp(size_t size)

Bikeshed: Not sure this name is very description. Perhaps reserve_stack_aligned() would be better. Not a big deal though. Patches 1,4 look fine otherwise.