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Keep boot parameters in ARM trampoline code

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Currently boot parameters (r0 - r3) are forgotten in ARM trampoline code.
This patch save them at startup and restore them before jumping into kernel
_start() routine.
This is usefull when booting with Linux ABI and/or custom bootloader.

Submitted by:	Grégory Soutadé <soutade@gmail.com>
Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D7395
This commit is contained in:
manu 2016-08-19 18:02:36 +00:00
parent b3cc80b493
commit 5292986b0f
1 changed files with 31 additions and 4 deletions
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35
sys/arm/arm/elf_trampoline.c
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@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
#include <machine/pte-v4.h> #include <machine/pte-v4.h>
#include <machine/cpufunc.h> #include <machine/cpufunc.h>
#include <machine/armreg.h> #include <machine/armreg.h>
#include <machine/cpu.h>
extern char kernel_start[]; extern char kernel_start[];
extern char kernel_end[]; extern char kernel_end[];
@ -47,7 +48,7 @@ extern void *_end;
void _start(void); void _start(void);
void __start(void); void __start(void);
void __startC(void); void __startC(unsigned r0, unsigned r1, unsigned r2, unsigned r3);
extern unsigned int cpu_ident(void); extern unsigned int cpu_ident(void);
extern void armv6_idcache_wbinv_all(void); extern void armv6_idcache_wbinv_all(void);
@ -124,6 +125,10 @@ static int arm_dcache_l2_nsets;
static int arm_dcache_l2_assoc; static int arm_dcache_l2_assoc;
static int arm_dcache_l2_linesize; static int arm_dcache_l2_linesize;
/*
* Boot parameters
*/
static struct arm_boot_params s_boot_params;
extern int arm9_dcache_sets_inc; extern int arm9_dcache_sets_inc;
extern int arm9_dcache_sets_max; extern int arm9_dcache_sets_max;
@ -172,12 +177,17 @@ bzero(void *addr, int count)
static void arm9_setup(void); static void arm9_setup(void);
void void
_startC(void) _startC(unsigned r0, unsigned r1, unsigned r2, unsigned r3)
{ {
int tmp1; int tmp1;
unsigned int sp = ((unsigned int)&_end & ~3) + 4; unsigned int sp = ((unsigned int)&_end & ~3) + 4;
unsigned int pc, kernphysaddr; unsigned int pc, kernphysaddr;
s_boot_params.abp_r0 = r0;
s_boot_params.abp_r1 = r1;
s_boot_params.abp_r2 = r2;
s_boot_params.abp_r3 = r3;
/* /*
* Figure out the physical address the kernel was loaded at. This * Figure out the physical address the kernel was loaded at. This
* assumes the entry point (this code right here) is in the first page, * assumes the entry point (this code right here) is in the first page,
@ -211,8 +221,15 @@ _startC(void)
/* Temporary set the sp and jump to the new location. */ /* Temporary set the sp and jump to the new location. */
__asm __volatile( __asm __volatile(
"mov sp, %1\n" "mov sp, %1\n"
"mov r0, %2\n"
"mov r1, %3\n"
"mov r2, %4\n"
"mov r3, %5\n"
"mov pc, %0\n" "mov pc, %0\n"
: : "r" (target_addr), "r" (tmp_sp)); : : "r" (target_addr), "r" (tmp_sp),
"r" (s_boot_params.abp_r0), "r" (s_boot_params.abp_r1),
"r" (s_boot_params.abp_r2), "r" (s_boot_params.abp_r3),
: "r0", "r1", "r2", "r3");
} }
#endif #endif
@ -487,6 +504,7 @@ load_kernel(unsigned int kstart, unsigned int curaddr,unsigned int func_end,
vm_offset_t lastaddr = 0; vm_offset_t lastaddr = 0;
Elf_Addr ssym = 0; Elf_Addr ssym = 0;
Elf_Dyn *dp; Elf_Dyn *dp;
struct arm_boot_params local_boot_params;
eh = (Elf32_Ehdr *)kstart; eh = (Elf32_Ehdr *)kstart;
ssym = 0; ssym = 0;
@ -555,6 +573,12 @@ load_kernel(unsigned int kstart, unsigned int curaddr,unsigned int func_end,
if (!d) if (!d)
return ((void *)lastaddr); return ((void *)lastaddr);
/*
* Now the stack is fixed, copy boot params
* before it's overrided
*/
memcpy(&local_boot_params, &s_boot_params, sizeof(local_boot_params));
j = eh->e_phnum; j = eh->e_phnum;
for (i = 0; i < j; i++) { for (i = 0; i < j; i++) {
volatile char c; volatile char c;
@ -604,7 +628,10 @@ load_kernel(unsigned int kstart, unsigned int curaddr,unsigned int func_end,
"mcr p15, 0, %0, c1, c0, 0\n" /* CP15_SCTLR(%0)*/ "mcr p15, 0, %0, c1, c0, 0\n" /* CP15_SCTLR(%0)*/
: "=r" (ssym)); : "=r" (ssym));
/* Jump to the entry point. */ /* Jump to the entry point. */
((void(*)(void))(entry_point - KERNVIRTADDR + curaddr))(); ((void(*)(unsigned, unsigned, unsigned, unsigned))
(entry_point - KERNVIRTADDR + curaddr))
(local_boot_params.abp_r0, local_boot_params.abp_r1,
local_boot_params.abp_r2, local_boot_params.abp_r3);
__asm __volatile(".globl func_end\n" __asm __volatile(".globl func_end\n"
"func_end:"); "func_end:");