diff options
authorTony Lindgren <tony@atomide.com>2015-06-11 11:47:53 -0700
committerSasha Levin <sasha.levin@oracle.com>2015-06-11 20:51:53 -0400
commit6d1637919e07a42598bebd1c04a9c565cc7ea6da (patch)
parent25798d3d216334361a51ac37429a83c1faa5e97d (diff)
ARM: OMAP3: Fix booting with thumb2 kernel
We get a NULL pointer dereference on omap3 for thumb2 compiled kernels: Internal error: Oops: 80000005 [#1] SMP THUMB2 ... [<c046497b>] (_raw_spin_unlock_irqrestore) from [<c0024375>] (omap3_enter_idle_bm+0xc5/0x178) [<c0024375>] (omap3_enter_idle_bm) from [<c0374e63>] (cpuidle_enter_state+0x77/0x27c) [<c0374e63>] (cpuidle_enter_state) from [<c00627f1>] (cpu_startup_entry+0x155/0x23c) [<c00627f1>] (cpu_startup_entry) from [<c06b9a47>] (start_kernel+0x32f/0x338) [<c06b9a47>] (start_kernel) from [<8000807f>] (0x8000807f) The power management related assembly on omaps needs to interact with ARM mode bootrom code, so we need to keep most of the related assembly in ARM mode. Turns out this error is because of missing ENDPROC for assembly code as suggested by Stephen Boyd <sboyd@codeaurora.org>. Let's fix the problem by adding ENDPROC in two places to sleep34xx.S. Let's also remove the now duplicate custom code for mode switching. This has been unnecessary since commit 6ebbf2ce437b ("ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+"). And let's also remove the comments about local variables, they are now just confusing after the ENDPROC. The reason why ENDPROC makes a difference is it sets .type and then the compiler knows what to do with the thumb bit as explained at: https://wiki.ubuntu.com/ARM/Thumb2PortingHowto Reported-by: Kevin Hilman <khilman@kernel.org> Tested-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Tony Lindgren <tony@atomide.com> (cherry picked from commit d8a50941c91a68da202aaa96a3dacd471ea9c693) Cc: <stable@vger.kernel.org> # v3.18+ Signed-off-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
1 files changed, 2 insertions, 20 deletions
diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index d1dedc8195ed..eafd120b53f1 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -203,23 +203,8 @@ save_context_wfi:
ldr r1, kernel_flush
blx r1
- /*
- * The kernel doesn't interwork: v7_flush_dcache_all in particluar will
- * always return in Thumb state when CONFIG_THUMB2_KERNEL is enabled.
- * This sequence switches back to ARM. Note that .align may insert a
- * nop: bx pc needs to be word-aligned in order to work.
- */
- THUMB( .thumb )
- THUMB( .align )
- THUMB( bx pc )
- THUMB( nop )
- .arm
b omap3_do_wfi
- * Local variables
- */
.word omap3_do_wfi_sram
@@ -364,10 +349,7 @@ exit_nonoff_modes:
* ===================================
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
- * Local variables
- */