4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 0b15394475e3bcaf35ca4bf22fc55d56df67224e ]
Testing has shown, that when using mainline U-Boot on MT7688 based boards, the system may hang or crash while mounting the root-fs. The main issue here is that mainline U-Boot configures EBase to a value near the end of system memory. And with CONFIG_CPU_MIPSR2_IRQ_VI disabled, trap_init() will not allocate a new area to place the exception handler. The original value will be used and the handler will be copied to this location, which might already be used by some userspace application.
The MT7688 supports VI - its config3 register is 0x00002420, so VInt (Bit 5) is set. But without setting CONFIG_CPU_MIPSR2_IRQ_VI this bit will not be evaluated to result in "cpu_has_vi" being set. This patch now selects CONFIG_CPU_MIPSR2_IRQ_VI on MT7620/8 which results trap_init() to allocate some memory for the exception handler.
Please note that this issue was not seen with the Mediatek U-Boot version, as it does not touch EBase (stays at default of 0x8000.0000). This is strictly also not correct as the kernel (_text) resides here.
Signed-off-by: Stefan Roese sr@denx.de [paul.burton@mips.com: s/beeing/being/] Signed-off-by: Paul Burton paul.burton@mips.com Cc: John Crispin blogic@openwrt.org Cc: Daniel Schwierzeck daniel.schwierzeck@gmail.com Cc: Ralf Baechle ralf@linux-mips.org Cc: linux-mips@linux-mips.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/mips/ralink/Kconfig | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/mips/ralink/Kconfig b/arch/mips/ralink/Kconfig index 813826a456ca..55a5fee781e8 100644 --- a/arch/mips/ralink/Kconfig +++ b/arch/mips/ralink/Kconfig @@ -38,6 +38,7 @@ choice
config SOC_MT7620 bool "MT7620/8" + select CPU_MIPSR2_IRQ_VI select HW_HAS_PCI
config SOC_MT7621