talos-skiboot/libc/string/Makefile.inc, branch master

build: use thin archives rather than incremental linking

2018-03-01T02:28:39+00:00

This changes to build system to use thin archives rather than incremental linking for built-in.o, similar to recent change to Linux. built-in.o is renamed to built-in.a, and is created as a thin archive with no index, for speed and size. All built-in.a are aggregated into a skiboot.tmp.a which is a thin archive built with an index, making it suitable or linking. This is input into the final link. The advantags of build size and linker code placement flexibility are not as great with skiboot as a bigger project like Linux, but it's a conceptually better way to build, and is more compatible with link time optimisation in toolchains which might be interesting for skiboot particularly for size reductions. Size of build tree before this patch is 34.4MB, afterwards 23.1MB. Signed-off-by: Nicholas Piggin Signed-off-by: Stewart Smith

libc/string: add memcpy_from_ci()

2016-10-05T03:42:26+00:00

This adds memcpy_from_ci, a cache inhibited version of memcpy, required by secure boot. The secure boot verification code is stored in a secure ROM and the logic that contains the ROM within the processor is implemented in a way that it only responds to CI (cache inhibited) operations. Due to performance issues we copy the verification code from the secure ROM to RAM and we use memcpy_ci for that. What makes memcpy_ci vs ordinary memcpy? memcpy copies data like in the example below and the compiler translates that to load instructions that are not cache inhibited (e.g. lbzx - load byte and zero indexed). In other words, the data is cached. a[i] = b[i] memcpy_ci copies data using the cache inhibited version of load instructions: in_8() and in_be32(), both defined in include/io.h. These functions use lbzcix and lwzcix assembly instructions, respectively. In this case, the data is not cached as required by the logic that contains the ROM. *((uint8_t*) destp) = in_8((uint8_t*)srcp); *((uint32_t*) destp) = in_be32((uint32_t*)srcp) Signed-off-by: Claudio Carvalho Signed-off-by: Stewart Smith

Initial commit of Open Source release

2014-07-02T05:36:20+00:00

Signed-off-by: Benjamin Herrenschmidt