Am Montag, 27. März 2023, 18:49:33 CEST schrieb Andy Chiu: > From: Greentime Hu <greentime.hu@xxxxxxxxxx> > > This patch facilitates the existing fp-reserved words for placement of > the first extension's context header on the user's sigframe. A context > header consists of a distinct magic word and the size, including the > header itself, of an extension on the stack. Then, the frame is followed > by the context of that extension, and then a header + context body for > another extension if exists. If there is no more extension to come, then > the frame must be ended with a null context header. A special case is > rv64gc, where the kernel support no extensions requiring to expose > additional regfile to the user. In such case the kernel would place the > null context header right after the first reserved word of > __riscv_q_ext_state when saving sigframe. And the kernel would check if > all reserved words are zeros when a signal handler returns. > > __riscv_q_ext_state---->| |<-__riscv_extra_ext_header > ~ ~ > .reserved[0]--->|0 |<- .reserved > <-------|magic |<- .hdr > | |size |_______ end of sc_fpregs > | |ext-bdy| > | ~ ~ > +)size ------->|magic |<- another context header > |size | > |ext-bdy| > ~ ~ > |magic:0|<- null context header > |size:0 | > > The vector registers will be saved in datap pointer. The datap pointer > will be allocated dynamically when the task needs in kernel space. On > the other hand, datap pointer on the sigframe will be set right after > the __riscv_v_ext_state data structure. > > Co-developed-by: Vincent Chen <vincent.chen@xxxxxxxxxx> > Signed-off-by: Vincent Chen <vincent.chen@xxxxxxxxxx> > Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx> > Suggested-by: Vineet Gupta <vineetg@xxxxxxxxxxxx> > Suggested-by: Richard Henderson <richard.henderson@xxxxxxxxxx> > Co-developed-by: Andy Chiu <andy.chiu@xxxxxxxxxx> > Signed-off-by: Andy Chiu <andy.chiu@xxxxxxxxxx> > Acked-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> Acked-by: Heiko Stuebner <heiko.stuebner@xxxxxxxx> Tested-by: Heiko Stuebner <heiko.stuebner@xxxxxxxx>
