From f9c4ff2ab9fe433d44ebbc2e3c2368a49df44798 Mon Sep 17 00:00:00 2001 From: Barry Song Date: Sat, 31 Jul 2021 00:51:31 +1200 Subject: arm64: fix the doc of RANDOMIZE_MODULE_REGION_FULL Obviously kaslr is setting the module region to 2GB rather than 4GB since commit b2eed9b588112 ("arm64/kernel: kaslr: reduce module randomization range to 2 GB"). So fix the size of region in Kconfig. On the other hand, even though RANDOMIZE_MODULE_REGION_FULL is not set, module_alloc() can fall back to a 2GB window if ARM64_MODULE_PLTS is set. In this case, veneers are still needed. !RANDOMIZE_MODULE_REGION_FULL doesn't necessarily mean veneers are not needed. So fix the doc to be more precise to avoid any confusion to the readers of the code. Cc: Masami Hiramatsu Cc: Ard Biesheuvel Cc: Qi Liu Signed-off-by: Barry Song Reviewed-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20210730125131.13724-1-song.bao.hua@hisilicon.com Signed-off-by: Will Deacon --- arch/arm64/kernel/kaslr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kernel/kaslr.c') diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index cfa2cfde3019..418b2bba1521 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -162,7 +162,9 @@ u64 __init kaslr_early_init(void) * a PAGE_SIZE multiple in the range [_etext - MODULES_VSIZE, * _stext) . This guarantees that the resulting region still * covers [_stext, _etext], and that all relative branches can - * be resolved without veneers. + * be resolved without veneers unless this region is exhausted + * and we fall back to a larger 2GB window in module_alloc() + * when ARM64_MODULE_PLTS is enabled. */ module_range = MODULES_VSIZE - (u64)(_etext - _stext); module_alloc_base = (u64)_etext + offset - MODULES_VSIZE; -- cgit