From 6a3e9d392a0c3194ad66935afa8814571899351f Mon Sep 17 00:00:00 2001
From: Axel Heider <axelheider@gmx.de>
Date: Sun, 6 Feb 2022 21:17:31 +0100
Subject: [PATCH] elfloader/risc-v: unify multicore stacks

- declare stack fully in C code
- use one array that holds all stack
- use CONFIG_KERNEL_STACK_BITS for size

Signed-off-by: Axel Heider <axelheider@gmx.de>
---
 elfloader-tool/src/arch-riscv/boot.c |  3 ++-
 elfloader-tool/src/arch-riscv/crt0.S | 25 ++++++++++---------------
 2 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/elfloader-tool/src/arch-riscv/boot.c b/elfloader-tool/src/arch-riscv/boot.c
index 7edac2a37..48085b8e8 100644
--- a/elfloader-tool/src/arch-riscv/boot.c
+++ b/elfloader-tool/src/arch-riscv/boot.c
@@ -57,7 +57,8 @@ unsigned long l2pt[PTES_PER_PT] __attribute__((aligned(4096)));
 unsigned long l2pt_elf[PTES_PER_PT] __attribute__((aligned(4096)));
 #endif
 
-char elfloader_stack_alloc[BIT(CONFIG_KERNEL_STACK_BITS)];
+/* Stacks for each core are set up in the assembly startup code. */
+char elfloader_stack[CONFIG_MAX_NUM_NODES * BIT(CONFIG_KERNEL_STACK_BITS)] __attribute__((aligned(4096)));
 
 /* first HART will initialise these */
 void const *dtb = NULL;
diff --git a/elfloader-tool/src/arch-riscv/crt0.S b/elfloader-tool/src/arch-riscv/crt0.S
index 69e8808e3..74e39a6e8 100644
--- a/elfloader-tool/src/arch-riscv/crt0.S
+++ b/elfloader-tool/src/arch-riscv/crt0.S
@@ -9,8 +9,11 @@
 
 .extern main
 .extern __global_pointer$
-.extern elfloader_stack_alloc
+.extern elfloader_stack
 .extern hsm_exists
+#if CONFIG_MAX_NUM_NODES > 1
+.extern next_logical_core_id
+#endif
 
 #define BIT(n) (1 << (n))
 
@@ -56,7 +59,7 @@ _start:
   mv s2, a1 /* preserve a1 (dtb) in s2 */
 
   /* Attach the stack to sp before calling any C functions */
-  la sp, (elfloader_stack_alloc + BIT(12))
+  la sp, (elfloader_stack + BIT(CONFIG_KERNEL_STACK_BITS))
 
 #ifdef CONFIG_IMAGE_BINARY
 /* Clear the BSS before we get to do anything more specific */
@@ -117,7 +120,7 @@ _start1: /* a0 must hold current hard ID passed by bootloader */
   /* This HART may be a different HART to the one that started at _start
    * If we've switched HARTs then the other HART will get a different stack
    * region in secondary_harts. */
-  la sp, (elfloader_stack_alloc + BIT(12))
+  la sp, (elfloader_stack + BIT(CONFIG_KERNEL_STACK_BITS))
   /* The C code expects the registers to be set up as:
    *   a0 = hart id
    *   a1 = dtb
@@ -125,15 +128,6 @@ _start1: /* a0 must hold current hard ID passed by bootloader */
   la s0, main
   jr s0
 
-#if CONFIG_MAX_NUM_NODES > 1
-.extern next_logical_core_id
-.data
-bootstack_secondary_cores:
-.align 12
-.space 4096 * (CONFIG_MAX_NUM_NODES - 1)
-#endif
-
-.text
 
 .global secondary_harts
 secondary_harts:
@@ -153,9 +147,10 @@ secondary_harts:
   amoadd.w a1, t2, (a1)
   li t2, CONFIG_MAX_NUM_NODES
   bge a1, t2, hsm_suspend_hart
-
-  slli t0, a1, 12
-  la sp, bootstack_secondary_cores
+  /* setup the hart specific stack pointer */
+  la sp, elfloader_stack
+  addi t0, a1, 1 /* increment by one because we need to set sp to the end */
+  slli t0, t0, CONFIG_KERNEL_STACK_BITS /* t0 = t0 * BIT(CONFIG_KERNEL_STACK_BITS) */
   add sp, sp, t0
   la s0, secondary_entry
   jr s0