> From: Heinrich Schuchardt [mailto:[email protected]] > Sent: Sunday, September 27, 2020 4:24 PM > To: Rick Jian-Zhi Chen(陳建志) > Cc: Simon Glass; Sean Anderson; Bin Meng; [email protected]; 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 <[email protected]> > Signed-off-by: Heinrich Schuchardt <[email protected]> > --- > 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 <[email protected]>
