> From: Heinrich Schuchardt [mailto:xypron.g...@gmx.de] > Sent: Sunday, September 27, 2020 4:24 PM > To: Rick Jian-Zhi Chen(陳建志) > Cc: Simon Glass; Sean Anderson; Bin Meng; u-boot@lists.denx.de; Alexander > Graf; Abner Chang; Heinrich Schuchardt > Subject: [PATCH v2 1/1] 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 <abner.ch...@hpe.com> > Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de> > --- > v2: > Saving and restoring the caller's x3 is already handled in mtrap.S. > efi_loader.h provides an empty fallback efi_restore_gd() function > if CONFIG_EFI_LOADER=n. > --- > arch/riscv/lib/interrupts.c | 3 +++ > 1 file changed, 3 insertions(+)
Reviewed-by: Rick Chen <r...@andestech.com>