From c48e9f310b950e39a91cea74b6708dd4fe2eb39c Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Sat, 26 Sep 2020 07:50:36 +0200 Subject: riscv: restore global data pointer in trap handler The gp register is used to store U-Boot's global data pointer. We should not assume that an UEFI application leaves the gp register unchanged as the UEFI specifications does not define who is the owner of the gp and tp registers. So the following sequence should be followed in the trap handler: * save the caller's gp register * restore the global data pointer * serve interrupts or print crash dump and reset * restore the caller's gp register Cc: Abner Chang Signed-off-by: Heinrich Schuchardt Reviewed-by: Bin Meng Reviewed-by: Rick Chen --- arch/riscv/lib/interrupts.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/riscv') diff --git a/arch/riscv/lib/interrupts.c b/arch/riscv/lib/interrupts.c index cd47e64..8ff40f0 100644 --- a/arch/riscv/lib/interrupts.c +++ b/arch/riscv/lib/interrupts.c @@ -111,6 +111,9 @@ ulong handle_trap(ulong cause, ulong epc, ulong tval, struct pt_regs *regs) { ulong is_irq, irq; + /* An UEFI application may have changed gd. Restore U-Boot's gd. */ + efi_restore_gd(); + is_irq = (cause & MCAUSE_INT); irq = (cause & ~MCAUSE_INT); -- cgit v1.1