The linker script collecting .init.rodata.* ahead of .init.rodata.cf_clobber accidentally causes __initconst_cf_clobber to be a no-op.
Rearrange the linker script to unbreak this. The IOMMU adjust_irq_affinities() hooks currently violate the safety requirement for being cf_clobber, by also being __initcall(). Consolidate to a single initcall using iommu_call() (satisfying the cf_clobber safety requirement), and also removes the dubious property that we'd call into both vendors IOMMU drivers on boot, relying on the for_each_*() loops to be empty for safety. With this fixed, an all-enabled build of Xen has 1681 endbr64's (1918 including .init.text) with 382 (23%) being clobbered during boot. Signed-off-by: Andrew Cooper <[email protected]> --- CC: Jan Beulich <[email protected]> CC: Roger Pau Monné <[email protected]> CC: Wei Liu <[email protected]> I was unsure whether to go common or x86 spefific IOMMU code, so went with the conservative option. The final hunk can trivially move if preferred. --- xen/arch/x86/xen.lds.S | 12 ++++++------ xen/drivers/passthrough/amd/iommu_init.c | 1 - xen/drivers/passthrough/vtd/iommu.c | 1 - xen/drivers/passthrough/x86/iommu.c | 6 ++++++ 4 files changed, 12 insertions(+), 8 deletions(-) diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S index 83def6541ebd..b15e5b67e4a4 100644 --- a/xen/arch/x86/xen.lds.S +++ b/xen/arch/x86/xen.lds.S @@ -210,6 +210,12 @@ SECTIONS DECL_SECTION(.init.data) { #endif + . = ALIGN(POINTER_ALIGN); + __initdata_cf_clobber_start = .; + *(.init.data.cf_clobber) + *(.init.rodata.cf_clobber) + __initdata_cf_clobber_end = .; + *(.init.rodata) *(.init.rodata.*) @@ -224,12 +230,6 @@ SECTIONS *(.initcall1.init) __initcall_end = .; - . = ALIGN(POINTER_ALIGN); - __initdata_cf_clobber_start = .; - *(.init.data.cf_clobber) - *(.init.rodata.cf_clobber) - __initdata_cf_clobber_end = .; - *(.init.data) *(.init.data.rel) *(.init.data.rel.*) diff --git a/xen/drivers/passthrough/amd/iommu_init.c b/xen/drivers/passthrough/amd/iommu_init.c index 657c7f619a51..2e5bffa732e7 100644 --- a/xen/drivers/passthrough/amd/iommu_init.c +++ b/xen/drivers/passthrough/amd/iommu_init.c @@ -831,7 +831,6 @@ int cf_check iov_adjust_irq_affinities(void) return 0; } -__initcall(iov_adjust_irq_affinities); /* * Family15h Model 10h-1fh erratum 746 (IOMMU Logging May Stall Translations) diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c index 6a65ba1d8271..f70d51580657 100644 --- a/xen/drivers/passthrough/vtd/iommu.c +++ b/xen/drivers/passthrough/vtd/iommu.c @@ -2119,7 +2119,6 @@ static int cf_check adjust_vtd_irq_affinities(void) return 0; } -__initcall(adjust_vtd_irq_affinities); static int __must_check init_vtd_hw(bool resume) { diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c index 58a422fb5f88..6ef580215bc2 100644 --- a/xen/drivers/passthrough/x86/iommu.c +++ b/xen/drivers/passthrough/x86/iommu.c @@ -462,6 +462,12 @@ bool arch_iommu_use_permitted(const struct domain *d) likely(!p2m_get_hostp2m(d)->global_logdirty)); } +static int cf_check __init adjust_irq_affinities(void) +{ + return iommu_call(&iommu_ops, adjust_irq_affinities); +} +__initcall(adjust_irq_affinities); + /* * Local variables: * mode: C -- 2.11.0
