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ARC: explicit'ify uboot support

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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2015-03-09 19:40:09 +05:30
parent fd1557923b
commit 036b2c5664
3 changed files with 18 additions and 1 deletions
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12
arch/arc/Kconfig
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@ -388,6 +388,18 @@ config ARC_DBG_TLB_MISS_COUNT
Counts number of I and D TLB Misses and exports them via Debugfs Counts number of I and D TLB Misses and exports them via Debugfs
The counters can be cleared via Debugfs as well The counters can be cleared via Debugfs as well
config ARC_UBOOT_SUPPORT
bool "Support uboot arg Handling"
default n
help
ARC Linux by default checks for uboot provided args as pointers to
external cmdline or DTB. This however breaks in absence of uboot,
when booting from Metaware debugger directly, as the registers are
not zeroed out on reset by mdb and/or ARCv2 based cores. The bogus
registers look like uboot args to kernel which then chokes.
So only enable the uboot arg checking/processing if users are sure
of uboot being in play.
config ARC_BUILTIN_DTB_NAME config ARC_BUILTIN_DTB_NAME
string "Built in DTB" string "Built in DTB"
help help

2
arch/arc/kernel/head.S
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@ -83,6 +83,7 @@ stext:
st.ab 0, [r5, 4] st.ab 0, [r5, 4]
1: 1:
#ifdef CONFIG_ARC_UBOOT_SUPPORT
; Uboot - kernel ABI ; Uboot - kernel ABI
; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2
; r1 = magic number (board identity, unused as of now ; r1 = magic number (board identity, unused as of now
@ -90,6 +91,7 @@ stext:
; These are handled later in setup_arch() ; These are handled later in setup_arch()
st r0, [@uboot_tag] st r0, [@uboot_tag]
st r2, [@uboot_arg] st r2, [@uboot_arg]
#endif
; setup "current" tsk and optionally cache it in dedicated r25 ; setup "current" tsk and optionally cache it in dedicated r25
mov r9, @init_task mov r9, @init_task

5
arch/arc/kernel/setup.c
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@ -319,13 +319,16 @@ static inline int is_kernel(unsigned long addr)
void __init setup_arch(char **cmdline_p) void __init setup_arch(char **cmdline_p)
{ {
#ifdef CONFIG_ARC_UBOOT_SUPPORT
/* make sure that uboot passed pointer to cmdline/dtb is valid */ /* make sure that uboot passed pointer to cmdline/dtb is valid */
if (uboot_tag && is_kernel((unsigned long)uboot_arg)) if (uboot_tag && is_kernel((unsigned long)uboot_arg))
panic("Invalid uboot arg\n"); panic("Invalid uboot arg\n");
/* See if u-boot passed an external Device Tree blob */ /* See if u-boot passed an external Device Tree blob */
machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */ machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */
if (!machine_desc) { if (!machine_desc)
#endif
{
/* No, so try the embedded one */ /* No, so try the embedded one */
machine_desc = setup_machine_fdt(__dtb_start); machine_desc = setup_machine_fdt(__dtb_start);
if (!machine_desc) if (!machine_desc)