On Tue, Feb 11, 2020 at 5:53 AM Joerg Roedel <joro@xxxxxxxxxx> wrote: > > From: Joerg Roedel <jroedel@xxxxxxx> > > The x86-64 ABI defines a red-zone on the stack: > > The 128-byte area beyond the location pointed to by %rsp is > considered to be reserved and shall not be modified by signal or > interrupt handlers. 10 Therefore, functions may use this area for > temporary data that is not needed across function calls. In > particular, leaf functions may use this area for their entire stack > frame, rather than adjusting the stack pointer in the prologue and > epilogue. This area is known as the red zone. > > This is not compatible with exception handling, so disable it for the > pre-decompression boot code. Acked-by: Andy Lutomirski <luto@xxxxxxxxxx> I admit that I thought we already supported exceptions this early. At least I seem to remember writing this code. Maybe it never got upstreamed? --Andy
